In 425 BC the Greek playwright Aristophanes wrote: "Ah! the Generals! they are numerous, but not good for much!"
Most generals appear to be vaguely aware that it is best to point their army in the general direction of an enemy. Beyond that "generalship" is often seriously lacking. The bulk of generals are little more than career bureaucrats who specialize in shining chairs with their asses. Add or take away one or two key generals out of any war and results can change radically.
A good example, take out U.S. Grant and William Tecumseh Sherman from the American Civil War and the South might have remained an independent nation.
So the question is, what if the invading Muslim Arabs had faced a younger Emperor Heraclius who had just crushed the Persian Empire? Facing him personally in the field at the peak of his powers as a general would have changed Middle East history. Or what if the great early Muslim commander Khalid ibn al-Walid had died of food poisoning years before the Arab invasions had started?
History could have been very different. As it was the other Eastern Roman Generals showed modest to little talent.
After successfully conquering Syria between 634 and 638, the Arabs turned their attention to Egypt. The attack on Africa took the Romans by surprise. Heraclius’s generals had advised him that the Muslims would need a generation to digest Persia before undertaking another wholesale conquest. The increasingly frail Emperor was forced to depend on his generals, and the result was complete disaster.
In 639, less than a year after the complete fall of the Sassanid Persian Empire, an army of some 4,000 commanded by Amr ibn al-A'as, under orders of Omar, began the invasion of the Diocese of Egypt. That relatively tiny force marched from Syria through El-Arish, easily took Farama, and from there proceeded to Bilbeis, where they were delayed for a month. But having captured Bilbeis, the Arabs moved again.
Crowned Caesar Flavius Heraclius Augustus in 610. Latin was still the official language of the military and government. The Emperor faced invasions by Persians, Avars, Spanish Visigoths and Muslim Arabs. The Emperor personally commanded Roman troops in an invasion into the heart of Persia. He crushed their Empire and forced Persian troops to evacuate the conquered Roman provinces of Egypt, Palestine, Syria and Mesopotamia.
Another 12,000 Muslim reinforcements were marching into Egypt to join with the 4,000 already there under Amr.. The smaller Arab force, commanded by a charismatic and tactically brilliant commander went behind enemy lines, and caused chaos all out of proportion to their size.
The Roman commander Theodore had built up a considerable army of perhaps 20,000 men around the fortress of Babylon.
Theodore had the opportunity to attack the smaller Arab army before the new army arrived. Instead out of fear? or excessive caution? Theodore remained inactive at Babylon.
The second army dispatched by Omar arrived at Heliopolis and began to lay siege to it. Amr retraced his route across the Nile River, and united his forces with those of the second army. They began to prepare for movement towards Alexandria – but scouts reported that Theodore and the Roman Army were finally on the move.
Why Theodore waited for the two smaller Arab armies to unite into one large army of 15,000 is not known. Perhaps Theodore was shamed by his officers for inaction.
Perhaps the morale of Theodore's troops was undermined by the reports of Arab victories against both the Persians and Romans in Syria and Mesopotamia.
So in July, 640 Theodore decided to march out of Babylon and take on the now united Arab force. He advanced across the plain to attack Heliopolis.
We do not know much about the Roman troops - how much cavalry, infantry or local militia for example.
What we do know is Amr fought a brilliant battle at Heliopolis.
When the Roman Army began approaching, Amr divided his army into three separate units, with one detachment under the command of a trusted commander, Kharija. Under the cover of darkness this unit marched abruptly east to nearby hills, where they effectively hid. This unit was to remain there until the Romans had begun the battle, at which point they were to fall on the Roman flank or rear, whichever was more vulnerable. The second detachment Amr ordered to the south, which would be the direction the Romans would flee if the battle went badly.
The two Arab flanking parties had moved in the dark and were not seen by the Romans.
The two main armies met in desperate hand hand-to-hand combat. Once the Roman forces initiated contact with Amr's forces and commenced an attack, the detachment of Kharija attacked the Theodore's rear, which was completely unexpected by the Romans.
Theodore had not kept scouts out, or, if he had, he ignored their warning of the approaching Arab horsemen.
This attack from the rear created utter chaos among the Roman ranks. As Theodore's troops attempted to flee to the south, they were attacked by the third detachment, which had been placed there for just such a purpose. This completed the final break-down and defeat of the Roman army, which fled in all directions.
Theodore survived, but with only a tiny fragment of his army, while the remainder was killed or captured. Many survivors retreated to the Fortress of Babylon.
In the battle's aftermath, most of southern and central Egypt fell to Amr's forces. The defeat at Heliopolis was crucial, as it removed the last Roman force standing between the Islamic invaders and the heart of Egypt. However, not only did the Battle of Heliopolis leave Egypt practically defenseless.
The defeat encouraged the disaffected natives, most of whom were Monophysite Christians and had suffered on-and-off persecution at the hands of Constantinople, to rise up against their Roman oppressors.
Although the Eastern Empire was certainly by lineage the Roman Empire, its traditions, language, and ruling elite, by this time, were Greek. The Greeks of Egypt, whose numbers could scarcely equal a tenth of the native population, were overwhelmed by the universal defection of those same natives from obedience to the Roman Empire. As Bury wrote in the History of the Later Roman Empire from Arcadius to Irene:
- ”The Greeks had ever been hated, they were no longer feared: the magistrate fled from his tribunal, the bishop from his altar; and the distant garrisons were surprised or starved by the surrounding multitudes.”
Bishop John of Nikiu said, "And thereupon the Moslem made their entry into Nakius, and took possession, and finding no soldiers (to offer resistance), they proceeded to put to the sword all whom they found in the streets and in the churches, men, women, and infants, and they showed mercy to none. And after they had captured (this) city, they marched against other localities and sacked them and put all they found to the sword. And they came also to the city of Sa, and there they found Esqutaws and his people in a vineyard, and the Moslem seized them and put them to the sword.
Sir Walter Scott was correct when he said “the fate of Byzantine Africa was decided at the Battle of Heliopolis.”
The permanent loss of the Egypt left the Roman Empire without an irreplaceable source of food and money.