Military service may often have been the business of rather older men than we might expect in the light of modern experience. Twentieth-century warfare was infamously the business of very young men. In Normandy in 1944, soldiers in their late twenties were regarded by their comrades as ‘old’ and the average age of the GIs in Vietnam was nineteen. British soldiers in the Falklands in 1982 were even younger: only eighteen on average. However, in the furnished cemeteries of the sixth century (CE) full weapon sets typically symbolise mature adult men (between about thirty and fifty, or even sixty). Later, Ripwin, a landowner in the middle Rhine area, first attests charters in 767 (CE), suggesting he must have reached legal majority (about fifteen years) by then. Twenty-five years afterwards, in 792/3, he was called out on campaign to Italy and made various dispositions about what was to happen if he did not return. Ripwin’s worries were reasonable enough; Italy was a graveyard for armies, if more through disease than battle. Nevertheless, Ripwin did come back – he appears in the documents until 806 – but these charters show that he was still serving in Charlemagne’s army until at least his forties.
Close fighting with spear and shield requires strength and stamina to be sure, but also, and possibly more importantly, cunning and the knowledge of how to attack and parry – knowing the moves. An experienced warrior can spot the type of attack being launched, parry it and riposte with a minimum of physical effort. He knows where and when to use physical effort, and not to waste it on wild, frenzied attacks. Except possibly against raw, untrained troops, accuracy and blade- or point-control is more important than mere ferocity. Repeated experience of battle made a warrior more likely to survive it. As will be seen, it was this accumulation of experience which made the Vikings such difficult foes to beat. It is very likely that the same factor made eighth-century Frankish armies so successful. Success breeds success. On the other hand, states whose armed forces had had little experience of warfare might find themselves at a distinct disadvantage when attacked by more hardened forces. Thus, it would seem, the easy success over Lombard armies enjoyed by battle-tested Frankish forces in the eighth century. The rapid collapse of the Avar kingdom in the 790s probably owed as much to the Avars’ generally peaceful and isolationist existence in the eighth century as to the clever strategies employed by Charlemagne and his commanders.
– Guy Halsall, Warfare and Society in the Barbarian West, 450-900. Warfare and History (Routledge: London and New York, 2003) pp. 35, 36
In antiquity, teenaged soldiers are often assigned to less demanding roles, like Polybius’ velites or Thucydides’ troops to man the Long Walls, until their bodies and minds had matured and they had gained the experience to survive prolonged combat at close quarters without flinching. Classical Greeks thought that the one thing young soldiers were good at was chasing down light-armed opponents, and in that they agreed with modern athletes.
Experience was probably the main reason that Athenian armies were so successful in the fifth century BCE. Except in Sparta and the Roman army after Augustus, military training was not institutionalized, so in two generations of peace key practical knowledge was generally lost. That knowledge could be reinvented, but Thucydides’ harsh teacher charged tuition fees in blood.
Further Reading: Jolene McLeod has an article somewhere arguing that while Plutarch’s story about Eumenes’ Silver Shields being ‘none of them under sixty years of age’ (Eumenes, 16.4) was probably exaggerated, plenty of middle-aged men served as combat soldiers in antiquity. Reyes Bertolin has researched ancient athletes who tend to be young adults as the games professionalized and competition became more intense.