Dedicated to the military history and civilization of the Eastern Roman Empire (330 to 1453)

"Time in its irresistible and ceaseless flow carries along on its flood all created things and drowns them in the depths of obscurity."

- - - - Princess Anna Comnena (1083–1153) - Byzantine historian

Tuesday, January 22, 2013

The Arab Siege of Nicaea

Umayyad Arab infantry early 8th century.

Fanatical Muslim Armies Thrust Deep into the Empire

The Siege of Nicaea of 727 was an unsuccessful attempt by the Umayyad Caliphate to capture the Roman city of Nicaea, the capital of the Opsician Theme. Ever since its failure to capture the Roman  capital in 717–718, the Caliphate had launched a series of raids into Byzantine Asia Minor. In 727, the Arab army, led by one of the Caliph's sons, penetrated deep into Asia Minor, sacked two Roman fortresses and in late July arrived before Nicaea

Despite constant attacks for 40 days, the city held firm and the Arabs withdrew and returned to the Caliphate. The successful repulsion of the attack was a major boost for Roman Emperor Leo III the Isaurian's recently initiated campaign to abolish the veneration of icons in the Empire. Leo claimed it as evidence of divine favor for his policy. 

The siege of Nicaea marks also the high point of the Umayyad raids, as new threats and defeats on their far-flung frontiers diverted Umayyad strength elsewhere, while Roman power gradually recovered.

A section of the 5 miles of Roman walls still surrounding Nicaea.

The Arab Invasions of the Roman Empire
The Romans faced an endless series of Arab invasions into Asia Minor for decades on end.  The Romans fought wars with the Arabs over three continents:  Asia, Africa and Europe.  The invasions were horribly disruptive to the Empire's economy and its ability to collect taxes to support the state and military.  The Romans were virtually on a permanent war footing with the Arabs for centuries.
Ultimately the Arab invasions of Anatolia failed.  The Romans held on to Constantinople and all the important cities.  The Arabs were always forced to withdraw back into Syria.   


Following the failure of the year-long assault by the Umayyad armies on the Roman capital of Constantinople in 717–718, a short period of peace followed as the Umayyads licked their wounds, suppressed the rebellion of Yazid ibn al-Muhallab and re-assessed their priorities. When warfare on the Arab–Roman frontier recommenced in 720, the strategic focus of the Caliphate had shifted away from outright conquest. 
The Muslim raids across the Taurus Mountains into Byzantine Asia Minor still occurred regularly every spring and summer, sometimes accompanied by naval raids and followed by a winter expedition; they devastated large tracts of Asia Minor, and destroyed several fortresses. 

But the Arabs could not hold on to lands on the west side of the Taurus Mountains.  The Romans continued to hold fortified points throughout Asia Minor in the rear of the Arab armies.  With Roman troops at their rear they had to retreat back into Syria after each attack.  
Emperor Leo III the Isauian
faced wars in Asia Minor, the
Balkans and Italy.

The Roman Army  -  At the time of the siege the Eastern Roman Army would have numbered roughly from 90,000 to 100,000 plus men.  As strong as that sounds on paper, that force could not be gathered in one place to combat invaders.  (see chart below)

Roman units would have been thinly spread to defend a geographically huge Empire from Italy to Armenia to the Crimea to the Balkans.

Information on the structure of the army is guess work.  In past years the armored cavalry (cataphract) was the mailed fist of the Roman commanders.  But for 100 years the Romans had faced, and been defeated by, the fast and nimble light Arab cavalry.  

For the most part, the Romans had little interest in meeting the Arabs out in the open sword to sword.  We can assume that the bulk of military spending was directed into defensive fortifications and the infantry units needed to man the walls.  Light and heavy cavalry would have given a secondary role and used for scouting, smaller combats and frontier raids. 

Roman reaction to the Arab invasions during these years was necessarily passive. The Empire needed to nurse its strength against the vastly superior resources of the Caliphate while simultaneously defend many other parts of the nation from invasion.

The Romans did not obstruct or confront the raiding Arab armies, but rather retreated to well-fortified positions scattered throughout Asia Minor.
After the accession of Caliph Hisham (r. 723–743), the scale and ambition of the Muslim raids grew. One of the most prominent Umayyad leaders in these campaigns was Hisham's son Mu'awiyah, who led expeditions in 725 and 726, the first of which went as far west as Dorylaion.

A large Arab army from Syria thrust deep into the Roman Empire
and conducted a 40 day siege against Nicaea.

The Walls of Nicaea
Southern gate; triumphal arches were incorporated when the walls were built.

Roman troop deployments a few years before the Nicaea campaign.  By 727 the Exarchate of Africa had been captured by Muslim forces.

Invasion of 727 and the siege of Nicaea

In summer 727, another large-scale invasion was led by Mu'awiyah, with Abdallah al-Battal heading the vanguard of the army.  

The Byzantine chronicler Theophanes the Confessor claims that the vanguard alone numbered 15,000 men and the entire invasion force 100,000, clearly a grossly inflated number.

What is clear is this was a major invasion directed against The Opsician Theme, one of the most powerful themes in the Empire and located right next to Constantinople itself.  In the chart above the Roman troops near Constantinople could have been in the 40,000 man range.  Those Roman forces would have been divided among many cities to fend off Arab attacks.

The Arabs came prepared for battle with siege engines to knock down the walls of cities that opposed them.  It is fair to assume if the Arabs came to take cities then they would have brought enough troops to outnumber the Romans.  You do not lay siege to cities if the defenders outnumber you.  Call the size of the Arab army at no less than 40,000 men.   

The Arab army moved west into northwestern Asia Minor, and the vanguard under al-Battal attacked and sacked the town of Gangra in Paphlagonia and a place called in Arab sources Tabya (possibly the fort of Ateous in Phrygia). 

Gangra was razed to the ground, but during the attack on Tabya the Arabs, especially the Antiochene contingent, are said to have suffered heavy losses.

Arab Cavalry

Arab Mailed Archer

From there, the Arabs turned west towards Nicaea, the chief city of Bithynia and capital of the powerful Opsician Theme. 

The Arabs arrived before the city in late July, with al-Battal's vanguard preceding the main army. The Byzantines, probably under the command of the Count of the Opsicians, Artabasdos, did not meet them in the field, but instead retreated behind the city's walls.

The Arabs assaulted the city for forty days, employing siege engines which destroyed a part of the walls, but eventually failed to take it.  This one sentence summary is maddening, but historical records are few.  A 40 day siege was a major attack by any standards.  Also with part of the walls destroyed you know there was considerable hand-to-hand combat to keep the Arab infantry out of the city.  But again, we have no details, only our imagination.

In late August, they raised the siege and departed, taking along many captives and much booty. The 12th-century chronicle of Michael the Syrian claims that the city's inhabitants abandoned it and fled by ship through Lake Ascanius, whereupon the Arabs destroyed Nicaea, but this is clearly an error.


The repulsion of the Arab assault on Nicaea was an important success for the Byzantines. Emperor Leo III the Isaurian (r. 717–741) regarded the city's survival as a sign of divine favor towards his newly instituted iconoclastic policies, and was encouraged to drive them further. 

This is probably related to an incident mentioned in the account of Theophanes, where a certain Constantine, who served as a groom (strator) to Artabasdos, threw a stone on an icon of the Virgin Mary and then trampled on it. The soldier was killed the next day by a catapult, a fact which Theophanes reports as evidence of divine vengeance. However, this passage shows strong signs of tampering by the fervently anti-iconoclast Theophanes, from what was probably originally a pro-iconoclast story.
Militarily, the siege of Nicaea was the high-water-mark of the post-718 Umayyad raids. Never again would Umayyad armies penetrate as deeply into Asia Minor. 

Increasingly thereafter the Syro-Jaziran army, that provided the manpower for the raids against Byzantium, was diverted in the hard and fruitless wars against the Khazars in the Caucasus: the Khazars inflicted a heavy defeat on the Muslims in 730.  

A Byzantine–Khazar alliance was sealed by the marriage of Leo III's son and heir Constantine V (r. 741–775) with the Khazar princess Irene shortly after. 

Roman strength also revived as the Muslim military situation on all fronts of the over-extended Caliphate deteriorated. Consequently, in the 730s, Arab raids were mostly limited to the immediate frontier regions and their successes became fewer, until in 740 the Byzantines inflicted a heavy defeat against the largest invasion force assembled after 718 at the Battle of Akroinon.

Byzantine troops in the 7th Century.

1. Armored infantryman:

The 7th century was another period from which few illustrations survive. The best-equipped infantry appear to have had short-sleeved mail hauberks and remarkably large shields, plus spears and swords. This man's helmet is based upon one found in Central Europe which may be of Byzantine form. The addition of the mail aventail is hypothetical, reflecting a high degree of Turkish and specifically Avar influence. His sword is based upon an unusual Scandinavian form which is itself likely to reflect Byzantine origins. 

2. Armored cavalryman:

This trooper has been given a plumed cap over his helmet, as worn by warriors from Iran and the Caucasus. This could be the explanation for the otherwise extraordinary outlines of many helmets seen in 7th-9th century Byzantine art. Turkish and Avar influences can be seen on the belt, sword and bowcase, as shown by surviving fragments and pictorial sources.

3. Noble commander, late 7th century:

One remarkable and recently discovered fragment of wall painting sheds light on the costume of the 7th century Byzantine elite though not, unfortunately, on their military equipment. A long tunic with richly embroided claves and three-quarter sleeves was worn over a long-sleeved shirt, either with soft riding boots or, as here, with highly decorated shoes indicating high status. The practice of impaling the head and hands of a defeated rebel, presumably as a warning to others, seems to have been common in Byzantium at this time.

8th to 9th Centuries

The first defensive campaigns fought against the first Islamic armies took a certain form, with the imperial forces struggling to match the mobility and speed of the Arab raiders, who were able to deprave the Roman commanders of the initiative not simply by virtue of their fast-moving, hard-hitting tactics, but also because the type of warfare they practised made any notion of a regular front untenable.

The Arab Islamic conquests radically altered the strategic and political geography of the whole east Mediterranean region. The complete failure of attempts to meet and drive back the invaders in open battle induced a major shift in strategy whereby open confrontation with the Muslim armies were avoided. The comitatenses field armies were first withdrawn to north Syria and Mesopotamia, shortly thereafter back to the line of the Taurus and Anti-Taurus ranges.

By the mid-640s the armies which had operated in Syria, Mesopotamia and Palestine had been withdrawn into Anatolia. The regions across which they were based were determined by the ability of these districts to provide for the soldiers in terms of supplies and other requirements. The field forces thus came to be quartered across Asia Minor and Thrace, where they were referred to by the Greek term for these districts, themata or themes.

The themes were at first merely groupings of provinces across which different armies were based. By the latter 8th century some elements of fiscal as well as military administration were set up on a thematic basis, although the late Roman provinces continued to subsist.

City wall around Nicaea

Nicaea Northern city gate, 3 of the 4 gates survive, restricted to pedestrians.

Roman aqueducts used until the 1970s, this one is outside the eastern gate.

Ruins of the ancient Hagia Sophia, where the First Ecumenical Council met in Nicaea.

The Nicaea theater was supported by arches as the land was flat; note entrance for beasts.


One of Alexander the Great's generals founded the city in 316 BC, naming it Antigonela for himself. When taken by another general, it was named Nicaea for his wife. Nicaea became an important religious center following Constantine's edit of tolerance for Christianity in AD 313. The city has been important in the Roman, Byzantine, Seljuk, and Ottoman empires.

Located on the eastern shore of Lake Iznik, the city has long been a stopping place on the route between Constantinople and Anatolia. The area surrounding Nicaea is fertile with rich agriculture.
When controversy arose about the nature of Jesus Christ, Constantine called the first Ecumenical Council to Nicaea in AD 325 to settle the issue. All the bishops came, meeting for two months in the Senatus Palace, now submerged in Lake Iznik. The council affirmed Christ's divinity and established what is now known as the Nicene Creed. Nicaea hosted another Ecumenical Council in 787, that rejected iconoclasm, thus permitting the use of icons in worship. This second Nicaean council met in Hagia Sophia.

In 1075 the Seljuk commander Süleyman Sah I changed Nicaea's name to Iznik and made it his capital. Through the years, particularly in the 16th and 17th centuries, Iznik has been renown for tiles and ceramics that have greatly influenced decoration in mosques and palaces throughout Turkey. Described as the third 'holy city' after Jerusalem and the Vatican, the Second Vatican Council in 1962, declared Iznik a 'holy city' for Christians.

Siege of Nicaea (727)        Opsician Theme        Umayyad Caliphate

Friday, January 11, 2013

Harput Castle - Roman / Byzantine Fortress

The Castle of Harput
The isolated rock upon which a castle was later built, has been a
fortified site since the 9th century BC. 

The Roman and Byzantine Fortress of Harput

The Castle of Harput is located at the town of Elâzığ (Turkish pronunciation: [eˈlazɯː]; Armenian: Խարբերդ; Kh'arberd/Harput, Kurdish: Elezîz/Xarpêt , Syriac: ܟܪܦܘܬ; Kharpūṭ/Ḥarfūṭ).

Elazig is a city in Eastern Anatolia, Turkey and the administrative center of Elâzığ Province.

The city of Elâzığ was founded among the skirts of the hill on which the historical Harput Castle was constructed. According to the present historical sources, the most ancient inhabitants of Harput was the Hurrian nation who settled in these parts in c2000 B.C.

Harput, and its surrounding region was part of the kingdom of Urartu at the period of its maximum extension.

The ancient town and citadel called Kharput (Kharpert), which means "rocky fortress" in Armenian, was built by the first Armenian kings about five kilometers from modern Elâzığ.

However, very little written material about this city reached our day. It is possible that Harput stands on or is near the site of Carcathio-certa in Sophene, reached by Corbulo in A.D. 65. The early Muslim geographers knew it as Hisn Ziyad, but the Armenian name, Khartabirt or Kharbirt, whence Kharput and Harput, was generally adopted in time.

The isolated rock, upon which a castle was built later on, has been a fortified site since the 9th century BC.

A strong point like Harput would have been part of both the Roman and Byzantine defensive systems.  The castle exists.  You can see it for yourself.  But I can find near zero information about it.

There are so many questions about Byzantium and its wars that are lost to history.  Unfortunately Procopius of Caesarea (500 – c. AD 565) was the last, and almost only, real historian for the eastern empire.

Eastern Anatolia would have seen many huge military campaigns from Roman to Byzantine times.  This area saw multiple wars with the Persian Empire, Arabs and Turks.  A military strongpoint like Harput would have been involved in defense against those invasions.  When captured the castle would then have become an occupied strong point for the enemies of Rome.  There is a story to be told, but we will never know it.

After the 1071 Battle of Manzikert the region was occupied by Turkish tribes in 1085 and Roman troops in the area were withdrawn to defend the cities closer to the center of Anatolia, the coastal zones and Constantinople. 

The Romans left after 900 years never to return.  The eastern military themes permanently became Muslim and Turkish.

Harput - Over 900 years of Roman Rule
The Roman Empire had control of the Anatolia area around Harput for
about 900 years.  There were endless battles and invasions, but there is zero
information about the castle and its military history.  

In later years William of Tyre wrote that Joscelin I, Count of Edessa (Jocelyn) of Courtenay, and King Baldwin II of Jerusalem were prisoners of the Amir Balak in Kharput's castle and that they were rescued by their Armenian allies. William of Tyre calls the place Quart Piert or Pierre.

The Çubukoğulları, Artuqids and Ottomans ruled in the region..

Harput became part of a small emirate ruled by the Cubuko who were vassals of the Sultanate of Rum; later on the town was occupied by the Artukids, who were based in Mardin and Diyarbakir; Harput was ruled by a separate branch of the Artukids and during this period, the town flourished and its main monuments were built.

In 1234 Harput was annexed by the Sultans of Rum, but in 1243 the Mongol invasion weakened their power and the town was eventually included in Dulgadir, an emirate based in Maras.

In 1465 Harput fell to Uzun Hasan, leader of the Ak Koyunlu (White Sheep federation), Turkmen tribes to whom Timur had assigned the region of Diyarbakir; the Ak Koyunlu came in contact with the Ottomans and they tried in vain to prevent the (last) Byzantine Empire of Trebizond from falling into Ottoman hands; Uzun Hasan established relations with the Republic of Venice in order to contain the expansion of their common enemy.

View of the fortress

The Persian Empire
The Persian Sassanid Empire at its greatest extent ca. 620 AD.
Harput Castle would have been at the center of many great wars. In the early 600s the Persians conquered Roman provinces from Armenian to Palestine to Egypt.  The Roman Emperor Heraclius fought a devastating war of re-conquest over the Harput area.  But the written military history for the fortress is almost non-existent.
Mountains of books in excruciating detail have been written about the totally insignificant American Battle of the Little Big Horn.  But information about the great invasions and battles with the Persians, Slavs, Arabs and Turks often does not exist.  We can only guess at the at the endless acts of heroism and hand to hand combat that took place but are lost to history. 

In 1473, at the battle of Otluk Beli, Sultan Mehmet II led his army to a great victory against the Ak Koyunlu: the battle showed that the Ottomans had an edge on their eastern enemies: they used cannon and rifles whereas Uzun Hasan mainly relied on light cavalry.

Harput remained however in possession of the Ak Koyunlu; in 1507 it was occupied by the Safavids, who ruled over Persia from 1502 to 1722; their control of the town lasted only until 1516 when the Ottomans annexed Harput and the whole region; this occurred after the 1514 battle of Caldiran, in which Ottoman rifles and cannon exterminated the Safavid cavalry. Ak Koyunlu and Safavids regarded the use of cannon and rifles as dishonourable behaviour for a warrior.

Harput housed a large Armenian community who lived at the foot of the fortress; in the region several villages were inhabited almost entirely by Armenians; relations with the Muslim population were relatively good, because the Ottoman system of millet (religious community) granted the Armenians a certain degree of self government.

The Armenians had no reason to support the Safavids, the only enemy the Ottomans had in the east, and they were loyal to the Sultan.

(Elâzığ, Turkey)          (romeartlover.tripod.com)

Wednesday, January 2, 2013

The Byzantine Fortress of Dara

Dara, Necropolis
Dara or Daras was an important East Roman fortress city in Northern Mesopotamia on the border with the Sassanid Empire. Because of its great strategic importance, it featured prominently in the Roman-Persian conflicts of the 6th century, with the famous Battle of Dara taking place before its walls in 530. Today the Turkish village of Oğuz, a few kilometers North of the Syrian border, occupies its location.

The Eastern Roman Fortress of Dara

Dara or Daras was an important East Roman fortress city in northern Mesopotamia on the border with the Sassanid Empire. Because of its great strategic importance, it featured prominently in the Roman-Persian conflicts of the 6th century, with the famous Battle of Dara taking place before its walls in 530. Today the Turkish village of Oğuz, Mardin Province, occupies its location.

Dara Founded by Emperor Anastasius

During the Anastasian War in 502–506, the Roman armies fared badly against the Sassanid Persians. According to the Syriac Chronicle of Zacharias of Mytilene, the Roman generals blamed their difficulties on the lack of a strong base in the area, as opposed to the Persians, who held the great city of Nisibis (which until its cession in 363 had served the same purpose for the Romans).

Flavius Anastasius Augustus
Emperor 491 to 518

Therefore, in 505, while the Persian King Kavadh I was distracted in the East, Emperor Anastasius I decided to rebuild the village of Dara, only 18 kilometres westwards from Nisibis and just 5 km from the actual border with Persia, to be "a refuge for the army in which they might rest, and for the preparation of weapons, and to guard the country of the Arabs from the inroads of the Persians and Saracens".

Masons and workers from all over Mesopotamia were gathered and worked with great haste. The new city was built on three hills, on the highest of which stood the citadel, and endowed with great storehouses, a public bath, and water cisterns.

It took the name Anastasiopolis and became the seat of the Roman dux Mesopotamiae.

Reconstruction by Justinian

According to Procopius, the hasty construction of the original walls resulted in poor quality, and the severe weather conditions of the region exacerbated the problem, ruining some sections. Thus Emperor Justinian I was compelled to undertake extensive repairs to the city, afterwards renaming it Iustiniana Nova. The walls were rebuilt and the inner wall raised by a new storey, doubling its height to about 60 feet (20 m). The towers were strengthened and raised to three stories (ca. 100 feet) high, and a moat dug out and filled with water.
Dara is in Mardin Province, Turkey.

Justinian's engineers also diverted the nearby river Cordes towards the city by digging a canal. The river now flowed through the city, ensuring ample water supply.

At the same time, by means of diverting its flow to an underground channel which exited 40 miles (64 km) to the north, the garrison was able to deny water to a besieging enemy, a fact which saved the city on several occasions. To avert the danger of flooding, which had already once wrecked large parts of the city, an elaborate arch dam was built to contain it, one of the earliest known of its kind. In addition, barracks were built for the garrison, and two new churches were constructed, the "Great Church", and one dedicated to St Bartholomew.

Later history

The city was later besieged and captured by the Persians in 573-574, but was returned to the Romans by Khosrau II after the Roman-Persian treaty in 590. It was taken again by Khosrau in 604-05 after a nine-month siege, restored again to the Roman Empire by Heraclius, until it was finally captured in 639 by the Arabs. After this the city lost its military significance, declined and was eventually abandoned.

The Buildings of Justinian
By Procopius of Caesarea

Book II  -  In Book II Procopius below writes about the fortifications and cities on the Persian frontier

All the new churches which the Emperor Justinian built both in Constantinople and in its suburbs, and all those which, having been ruined by the passage of time, he restored, as well as all the other buildings which he erected here, have been described in the preceding Book.  From this point we must proceed to the defences with which he surrounded the farthest limits of the territory of the Romans.

Here indeed my narrative will be constrained to halt painfully and to labour with an impossible subject.  For it is not the pyramids which we are about to describe, those celebrated monuments of the rulers of Egypt, on which labour was expended for a useless show, but rather all the fortifications whereby this Emperor preserved the Empire, walling it about and frustrating the attacks of the barbarians on the Romans. And it seems to me not amiss to start from the Persian frontier.

When the Persians retired from the territory of the Romans, selling to them the city of Amida, as I have related in the Books on the Wars, the Emperor Anastasius selected a hitherto insignificant village close to the Persian boundary, Daras by name, and urgently set about enclosing it with a wall and making it into a city which should serve as a bulwark against the enemy. 

But since it was forbidden in the treaty which the Emperor Theodosius once concluded with the Persian nation, that either party should construct any new fortress on his own land where it bordered on the boundaries of the other nation, the Persians, citing the terms of the peace, tried with all their might to obstruct the work, though they were hard pressed by being involved in a war with the Huns.


The city walls and tower

So the Romans, observing that they were for this reason unprepared, pressed on the work of building all more keenly, being anxious to get ahead of the enemy before they should finish their struggle with the Huns and come against them.  Consequently, being fearful by reason of suspicion of the enemy, and continually expecting their attacks, they did not carry out the building with care, since the haste inspired by their extreme eagerness detracted from the stability of their work.  For stability is never likely to keep company with speed, nor is accuracy wont to follow swiftness. 

They therefore carried out the construction of the circuit-wall in great haste, not having made it fit to withstand the enemy, but raising it only to such a height as was barely necessary; indeed they did not even lay the stones themselves carefully, or fit them together as they should, or bind them properly at the joints with mortar.  So within a short time, since the towers could not in any way withstand the snows and the heat of the sun because of their faulty construction, it came about that the most of them fell into ruin. So were the earlier walls built at the city of Daras.

The engineers of Emperor Justinian diverted the river Cordes and constructed an underground cistern of huge proportions in Dara.

The Emperor Justinian perceived that the Persians, as far as lay in their power, would not permit this outpost of the Romans, which was a menace to them, to stand there, but they would of course assault it with all their might, and would use every device to conduct siege operations on even terms with the city; and that a great number of elephants would come with them, and these would bear wooden towers on their shoulders, under which they would stand, supporting them like foundations; and worse still, that they would be led about wherever the enemy needed them and would bear a fortress which would follow along wherever, according to the judgement of their masters, it should happen to be needed;  and that the enemy would mount these towers and shoot down upon the heads of the Romans inside the city, and attack them from a higher level; that, furthermore they would raise up artificial mounds against them, and would bring up all manner of siege-engines. 
And if any misfortune should befall the city of Daras, which was thrown out like an earthwork before the whole Roman Empire and was obviously placed as a threat to the enemy's land, the disaster for us would not stop there, but a great part of the State would be seriously shaken. For these reasons he wished to surround the place with defences in keeping with its practical usefulness.
The Roman and Persian Empires at the time of Justinian.
For centuries the armies of Persia and Rome fought wars over the Tigris–Euphrates Rivers area of Mesopotamia.  The Eastern Roman fortress of Dara was meant to provide a strong point and a block to Persian forces. 
First of all he rendered the wall (which, as I have said, was very low and therefore very easy for an enemy to assault) both inaccessible and wholly impregnable for an attacking force. For he contracted the original apertures of the battlements by inserting stones and reduced them to very narrow slits, leaving only traces of them in the form of tiny windows, and allowing them to open just enough for a hand to pass through, so that outlets were left through which arrows could be shot against assailants. 
Then above these he added to the wall a height of about thirty feet, not building the addition upon the whole thickness of the wall, lest the foundations should be overloaded by the excessive weight which bore upon them, so that the whole work would suffer some irreparable damage, but he enclosed the space at that level with courses of stones on the outside and constructed a colonnaded stoa (stoa) running all around the wall, and he placed the battlements above this portico, so that the wall really had a double roof throughout; and at the towers there were actually three levels for the men who defended the wall and repelled attacks upon it.  For at about the middle of each tower he added a rounded structure (sphairikon schêma) upon which he placed additional battlements, thus making the wall three-storeyed.
Then he observed that it had come about that many of the towers, as I have said, had fallen into ruin in a short time, yet it was entirely out of the question to pull them down, since the enemy were constantly in the neighbourhood watching their opportunity and continually scouting to see whether they might not find some part of the defences dismantled at any time. But he hit upon the following plan.  He left these towers in place, and outside each of them he cleverly erected another structure in the form of a rectangle, which was built securely and with every possible care, and thus, by means of a second set of defences, he safely enclosed those parts of the wall which had suffered. 
Dara, Necropolis, historical church-cave

But one of the towers, called the "Tower of the Guard," he pulled down at a favourable moment and rebuilt so that it was safe, and everywhere he removed the fear which had arisen from the weakness of the circuit-wall.  He also wisely added sufficient height, in due proportion, to the outworks.  And outside these he dug a moat, not in the way in which men are wont to make them, but only for a short distance and in a novel manner; and the reason for this I shall explain.
The greater part of the defences, as it happens, are in general unapproachable for an attacking party, since they do not stand on level ground and offer no favourable opportunity for assault to an approaching force; but they stand along a steep slope of a rough and precipitous character, where it is not possible for a mine to be dug or for any attack to be made.  But on the side which is turned toward south, the soil is deep and soft and consequently easy to mine, so that it makes the city assailable on this side. 

So in that place he dug a crescent-shaped moat, with sufficient breadth and depth and extending to a great distance, and joined either end of this to the outworks and filled it amply with water, rendering it altogether impassable for the enemy; and on its inner side he set up another outwork. On this the Romans take their stand and keep guard in time of siege, freed from anxiety for the circuit-wall and the other outwork which is thrown out before the main wall.  And it happened that between the main wall and the outwork, at the gate which faces toward the village of Ammodius, there lay a great mound of earth, under cover of which the enemy were able to be in large measure unobserved while making mines against the city under the circuit-wall.  This mound he removed from the spot and he cleared up the place thoroughly, and thus frustrated any secret attack on the wall by the enemy.

Thus did he construct these fortifications. He likewise made reservoirs for water both in the space between the circuit-wall and the outworks and also close by the church which is dedicated to the Apostle Bartholomew, situated toward the west.  And a river also flows from a suburb of the city which is two miles distant from it and is called Cordes. On either side of it rise two cliffs which are exceedingly rugged. This river flows down between the heights on either side of it all the way to the city, carried along the bases of the mountains, and for just this reason it cannot be turned aside or tampered with by the enemy; for there is no flat ground where they might be able to turn it from its course.
And it is drawn into the city in the following way.  They have constructed a large channel extending out from the circuit-wall, and covered the mouth of the conduit with a great number of the thickest possible iron bars, some upright and some horizontal; and thus they have arranged that the water can enter the city without endangering the fortifications.  In this way the water flows into the city and fills its reservoirs and then is conducted wherever the inhabitants wish, and finally flows out at another part of the city, the opening for its discharge being made like that by which it enters the city.
There was a certain Chryses of Alexandria, a skillful master-builder, who served the Emperor in his building operations and built most of the structures erected in the city of Daras and in the rest of the country. . . . . . He also built numerous barracks for the soldiers, in order that they might cause no annoyance whatever to the inhabitants.
Underground church
The old cisterns
Roman cistern in Dara
Originally an East Roman settlement Dara was a strategically important outpost of the Roman Empire and hence fortified by the Emperor Justinian. What makes it an interesting point to visit today is the vast necropolis, housing tombs of kings and families. Only a part rises above ground the rest still awaits excavation.

Justinian’s engineers also accomplished a great feat: they diverted the river Cordes to the city and constructed an underground cistern which takes your breath away because it’s so unexpected.

You descend stone steps, down, down and further down and then looked up at the massive structure which secured the water supply for the city.

(uchicago.edu - Procopius - Buildings)       (Dara - Mesopotamia)       (www.ac-nice.fr)