The soldiers of Rome’s amateur militia could easily fall into their SOP manipular array, which, while complex, was also familiar and legible: divided into three battle lines (triplex acies) by age class, and parsed into numbered maniples, each with its own well-defined command structure (centurions) and visual markers on the battlefield (signa). Most Roman commanders did not think of deviating much beyond this SOP: they more often than not fought by lining up the infantry in a triplex acies, with cavalry on the flanks and a screen of light infantry to the front. By and large, this battle plan worked quite well, providing even a mediocre general with a flexible array that could endure various shocks thanks to the built-in system of line relief and reinforcement and the final reserves of the triarii. Inevitably, some commanders also tinkered with the standard array, with varying degrees of success. In our first well-described battle involving the manipular legion, fought along the Bagradas River in 255 BC, the consul Atilius Regulus arrayed the maniples in an unusual depth, probably by stacking the centuries on top of each other. This tactic failed spectacularly, but it demonstrates that from an early point the components of the array might be rearranged to suit the circumstances and a general’s specific plan. The Battle of Ilipa in 206 BC was, by contrast, a spectacular success.
The strategic situation
Realizing that Spain was a major centre of gravity of Carthaginian power, as a font of both silver and recruits, the Roman senate dispatched an army to Spain in 218 BC, commanded by the Scipio brothers, Publius and Gnaeus. After some successes, both Scipios were killed, and their armies routed, in 212 during an ill-advised offensive. The survivors clung to a tenuous position along the
