preserve the Republic from danger". The term legion is derived from the Latin word legio, which ultimately means draft or levy. At first, there were only four Roman legions numbered "I" to "IIII" (with the fourth being written as such and not "IV"). The first legion was seen as the most prestigious. The bulk of the army consisted of citizens, who could not choose the legion to which they were allocated. Any man "from ages 16–46 was selected by ballot" and assigned to a legion. Until the Roman military disaster of 390 BC at the Battle of the Allia, Rome's army was organized similarly to the Greek phalanx. This was due to Greek influence in Italy "by way of their colonies". Patricia Southern quotes ancient historians Livy and Dionysius in saying that the "phalanx consisted of 3,000 infantry and 300 cavalries". Each man had to provide their equipment; the military equipment which they could afford determined which position they took in the battle. Politically they shared the same ranking system in the Comitia Centuriata. Roman army of the mid-Republic (c. 300–88 BC) The Roman army of the mid-Republic was also known as the "manipular army", or the "Polybian army", after the Greek historian Polybius, who provides the most detailed extant description of this phase. The Roman army started to have a full-time strength of 150,000 at all times and 3/4 of the rest were levied. During this period, the Romans, while maintaining the levy system, adopted the Samnite manipular organisation for their legions and also bound all the other peninsular Italian states into a permanent military alliance (see Socii). The latter were required to supply (collectively) roughly the same number of troops to joint forces as the Romans to serve under Roman command. Legions in this phase were always accompanied on campaign by the same number of allied alae (Roman non-citizen auxiliaries), units of roughly the same size as legions. After the Second Punic War (218–201 BC), the Romans acquired an overseas empire, which necessitated standing forces to fight lengthy wars of conquest and to garrison the newly gained provinces. Thus the army's character mutated from a temporary force based entirely on short-term conscription to a standing army in which the conscripts were supplemented by a large number of volunteers willing to serve for much longer than the legal six-year limit. These volunteers were mainly from the poorest social class,