Advertisements encouraging men and women to join the army emphasise that their religious beliefs, sexual orientation and emotional needs will be no barrier to making a career. Very nice too, but what sort of come-on is that? Is there no positive reason for joining up in the first place?

In the ancient world, war was a constant, and men had to be ready to die in battle for the very survival of their country, wives and children. So the motivation was very powerful — self-preservation. There were also rewards: the prospect of booty and honours. We hear of one Spurius Ligustinus, an ordinary foot-soldier from a one-acre farm who ‘four times within a few years held the rank of chief centurion; 34 times I was honoured by my commanders with rewards for bravery. I have received six civic crowns. I have fulfilled 22 years of service in the army…’ — and now at 50 he wanted to sign on again. Soldiers like that made the Roman army what it was.

When the Roman army was professionalised under the Emperor Augustus in the 1st century bc, selection became a big issue. The military analyst discussed preferences for recruits — age (from 16), background (countrymen preferred to city-dwellers, men from cooler climates rather than hotter), trade (no pastry cooks or weavers, plenty of blacksmiths and stonemasons) and physical stature. What was in it for them was a 20-year career, with five more optional, regular pay, proper health care and a pension in land or cash; and pride in being part of an army whose training, morale and track record were second to none, both protecting and expanding Roman power. As in all successful armies, ‘looking after your mates’ was at the root of it. Differences disappeared in the heat of battle.

The question that the advertising outfit has to answer is whether there is hard evidence that the issues which they headline are the ones that matter to enough of the (surely) tiny target cohort to persuade them to sign on. And what will any other potential cohort make of it?