least officially the three lines were based upon age and experience rather than social class. Young, unproven men would serve in the first line, older men with some military experience would serve in the second line, and veteran troops of advanced age and experience would serve in the third line. The heavy infantry of the maniples were supported by a number of light infantry and cavalry troops, typically 300 horsemen per manipular legion. The cavalry was drawn primarily from the richest class of equestrians. There was an additional class of troops who followed the army without specific martial roles and were deployed to the rear of the third line. Their role in accompanying the army was primarily to supply any vacancies that might occur in the maniples. The light infantry consisted of 1,200 unarmoured skirmishing troops drawn from the youngest and lower social classes. They were armed with a sword and a small shield, as well as several light javelins. Rome's military confederation with the other peoples of the Italian peninsula meant that half of Rome's army was provided by the Socii, such as the Etruscans, Umbrians, Apulians, Campanians, Samnites, Lucani, Bruttii, and the various southern Greek cities. Polybius states that Rome could draw on 770,000 men at the beginning of the Second Punic War, of which 700,000 were infantry and 70,000 met the requirements for cavalry. Rome's Italian allies would be organized in alae, or wings, roughly equal in manpower to the Roman legions, though with 900 cavalry instead of 300. A small navy had operated at a fairly low level after about 300, but it was massively upgraded about forty years later, during the First Punic War. After a period of frenetic construction, the navy mushroomed to a size of more than 400 ships on the Carthaginian ("Punic") pattern. Once completed, it could accommodate up to 100,000 sailors and embarked troops for battle. The navy thereafter declined in size. The extraordinary demands of the Punic Wars, in addition to a shortage of manpower, exposed the tactical weaknesses of the manipular legion, at least in the short term. In 217, near the beginning of the Second Punic War, Rome was forced to effectively ignore its long-standing principle that its soldiers must be both citizens and property owners. During the 2nd century, Roman territory saw an overall decline in population, partially due to the huge losses incurred during various wars.