It would be unheard of today for a 19 year old to command a major army. Most parents  are concerned enough about placing a 19 year old in charge of a motor vehicle.  Military commanders around the world today and for many centuries past have generally had decades of experience and hold authority partly on the basis of their seniority. Lee, MacArthur, Eisenhower, Cosgrove and Petraeus are all good examples. In the world of the ancient Greeks and Romans, however, it was not unusual for large armies to be led or even raised by young men who in modern terms were barely young men at all.

Perhaps the most famous example is Alexander the Great who began preparations in 336 BC to lead an army of 40,000 men against the Persians when he was 19. Alexander stamped his authority on the army early, winning an impressive victory over the Persians in Asia Minor only two years later at the age of 21. Over the next 11 years he would  lead this army as far south as Egypt and as far east as India. At no stage, it seems, does his youth seem to have been an impediment to leading such a large expeditionary force with many of his senior generals considerably older than him.

Nearly 300 years later, one of the ancient world’s greatest generals, Julius Caesar, wept in frustration over the sarcophagus of Alexander because the young Macedonian king had achieved more militarily by his late twenties than Caesar had by his early fifties.

Interestingly, Julius Caesar’s own adopted son and heir, Octavian/Augustus, would lead an army on the city of Rome at the age of 19 to avenge Caesar’s assassination in 44BC. Before the age of Caesar and Augustus, the Romans had prohibited anyone leading an army until they were 43 but as the Roman Empire expanded and more adventurous military leaders were required  this rule became more and more difficult to adhere to. Forty years earlier, Caesar’s great rival, Pompey, had raised a private army at the age of 23 and made himself indispensable to the most powerful Roman leader of the day, Sulla, despite the illegality of his actions.  This set the example which Octavian/Augustus would later follow and there are numerous cases in the Roman imperial period of teenagers and young men commanding armies.

How did such young men so successfully lead armies and would it be possible for a man of 19 today to lead an army of 40,000 men in a major territorial invasion? Life expectancy was clearly shorter for the Greeks and the Romans. For a male it was probably around 45, although there are known examples of people living beyond the age of 100 in antiquity. Young men of the Roman nobility, for example, came of age when they took the toga virilis at the age of 14. Greek and especially Roman society was also much more influenced and dominated by military matters with children of soldiers and the nobility sometimes marked out as infants for later military service and military service was a fundamental part of achieving political success. It might worry some of us today when 18 and 19 year olds organise overseas trips and set about beginning a career but spare a thought for Alexander the Great’s mother, Olympias, on the eve of his invasion of Asia.