[note 1] Earlier in the year, the new Roman navy had established naval superiority and used this advantage to invade the Carthaginian homeland, which roughly aligned with modern Tunisia in North Africa.

After landing on the Cape Bon Peninsula and conducting a successful campaign, the fleet returned to Sicily, leaving Regulus with 15,500 men to hold the lodgement in Africa over the winter.

[22] The Carthaginians were engaging in their traditional policy of waiting for their opponents to wear themselves out, in the expectation of then regaining some or all of their possessions and negotiating a mutually satisfactory peace treaty.

The war there had reached a stalemate, as the Carthaginians focused on defending their well-fortified towns and cities; these were mostly on the coast and so could be supplied and reinforced by sea without the Romans being able to use their superior army to interfere.

[24][25] The focus of the war shifted to the sea, where the Romans had little experience; on the few occasions they had previously felt the need for a naval presence they had relied on small squadrons provided by their allies.

[28] Naval victories at Mylae and Sulci, and their frustration at the continuing stalemate in Sicily, led the Romans to focus on a sea-based strategy and to develop a plan to invade the Carthaginian heartland in North Africa and threaten their capital, Carthage (close to what is now Tunis).

[30][31] The Roman fleet of 330 warships plus an unknown number of transport ships[32] sailed from Ostia, the port of Rome, in early 256 BC, commanded by the consuls for the year, Marcus Atilius Regulus and Lucius Manlius Vulso Longus.

[42] As a result of the sea battle, the Roman army, commanded by Regulus, landed in Africa near Aspis (modern Kelibia) on the Cape Bon Peninsula in summer 256 BC and began ravaging the Carthaginian countryside.

Hamilcar and two generals named Hasdrubal and Bostar were placed in joint command of an army which was strong in cavalry and elephants and was approximately the same size as the Roman force.

[53] It is not clear how the 15,000 infantry at Adys were constituted, but the modern historian John Lazenby suggests that they may have represented four slightly under-strength legions: two Roman and two allied.

Many would be from North Africa which provided several types of fighters including: close-order infantry equipped with large shields, helmets, short swords and long thrusting spears; javelin-armed light infantry skirmishers; close-order shock cavalry carrying spears; and light cavalry skirmishers who threw javelins from a distance and avoided close combat.

[57][58] Both Iberia and Gaul provided small numbers of experienced infantry: unarmoured troops who would charge ferociously, but had a reputation for breaking off if a combat was protracted.

[59] The precise makeup of the army at Adys is not known, but a few months later, at the battle of Tunis, the Carthaginians fielded 100 elephants, 4,000 cavalry and 12,000 infantry; the latter would have included the 5,000 veterans from Sicily and many citizen-militia.

[61] Determined to prevent the Romans further despoiling the countryside, the Carthaginians advanced to Adys, where they set up a fortified camp on a rocky hill near the town.

Modern historians point out that the Carthaginian generals would have been well aware of the strength of the legions when formed up in open battle and that to pause in a strong position while scouting the enemy and formulating a plan was not obviously a mistake.

[63] This was especially the case as their army was newly formed and not yet fully trained or used to operating together;[64] although the modern historian George Tipps describes this deployment as a "total misuse" of their cavalry and elephants.

[66] According to the military historian Nigel Bagnall, the cavalry and elephants were promptly evacuated, as it was recognised they would not be able to play any useful role, either in defending the fortifications or on the broken terrain of the hill more generally.

[68] Regulus, within sight of what he took to be a thoroughly defeated Carthage, demanded harsh terms: Carthage was to hand over Sicily, Sardinia and Corsica; pay all of Rome's war expenses; pay tribute to Rome each year; be prohibited from declaring war or making peace without Roman permission; have its navy limited to a single warship; but provide 50 large warships to the Romans on their request.

[73] The Roman fleet, in turn, was devastated by a storm while returning to Italy, with 384 ships sunk from their total of 464[note 8] and 100,000 men lost,[73][74] the majority non-Roman Latin allies.

[46] The war continued for a further 14 years, mostly on Sicily or the nearby waters, before ending with a Roman victory; the terms offered to Carthage were more generous than those proposed by Regulus.

[75] The question of which state was to control the western Mediterranean remained open, and when Carthage besieged the Roman-protected town of Saguntum in eastern Iberia in 218 BC, it ignited the Second Punic War with Rome.