An Ala was the term used during the mid- Roman Republic

Roman Republic

The Roman Republic was the period of the ancient Roman civilization where the government operated as a republic. It began with the overthrow of the Roman monarchy, traditionally dated around 508 BC, and its replacement by a government headed by two consuls, elected annually by the citizens and...

 (338-88 BC) to denote a military formation composed of conscripts from the socii, Rome's Italian military allies. A normal consul

Consul

Consul was the highest elected office of the Roman Republic and an appointive office under the Empire. The title was also used in other city states and also revived in modern states, notably in the First French Republic...

ar army during this period consisted of 2 legion

Roman legion

A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...

s, composed of Roman citizens only, and 2 allied alae. Alae were somewhat larger than normal legions (ca. 5400 v. ca. 4,500 men). From the time of the first Roman emperor

Roman Emperor

The Roman emperor was the ruler of the Roman State during the imperial period . The Romans had no single term for the office although at any given time, a given title was associated with the emperor...

, Augustus

Augustus

Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

 (ruled 30 BC - AD 14), the term ala was used in the professional imperial army to denote a much smaller (ca. 500), purely cavalry unit of the non-citizen auxilia corps, see Ala (Roman cavalry unit).

Mid-Republic

When, at a later date, the Roman armies were composed partly of Roman citizens and partly of Socii (allies from the rest of the Italian mainland), either Latini or Italici, it became the practice to marshal the Roman troops in the centre of the battle line and the Socii upon the wings. Armies of the middle republic would consist of two legions

Roman legion

A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...

 of Roman citizens and two legions of "ala", with the ala supplying thirty turmae of cavalry per legion, whereas the Roman provided only ten turmae. Hence ala and alarii denoted the contingent furnished by the allies

Allies

In everyday English usage, allies are people, groups, or nations that have joined together in an association for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out between them...

, both horse and foot, and the two divisions were distinguished as dextera ala (right wing) and sinistra ala (left wing) (Livy

Livy

Titus Livius — known as Livy in English — was a Roman historian who wrote a monumental history of Rome and the Roman people. Ab Urbe Condita Libri, "Chapters from the Foundation of the City," covering the period from the earliest legends of Rome well before the traditional foundation in 753 BC...

, xxvii.2 http://www.thelatinlibrary.com/livy/liv.27.shtml#2, Livy, xxv.21 http://www.thelatinlibrary.com/livy/liv.25.shtml#21, Livy xxxi.21 http://www.thelatinlibrary.com/livy/liv.31.shtml#21; Lips. de Milit. Rom. ii. dial. 7. We find in Livy x.40 http://www.thelatinlibrary.com/livy/liv.10.shtml#40, the expression cum cohortibus alariis ("with wing cohorts"), and in x. 43 http://www.thelatinlibrary.com/livy/liv.10.shtml#43, D. Brutum Scaevam legatum cum legione prima et decem cohortibus alariis equitatuque ire...jussit ("He ordered Decius Brutus Scaeva, legate, with the first legion and ten wing cohorts and the cavalry, to go and oppose said detachment...")..

Sources

This article is based on an article by William Ramsay, M.A., Professor of Humanity in the University of Glasgow on pp 73-74 of "A Dictionary of Greek and Roman Antiquities", John Murray, London, 1875, edited by William Smith, D.C.L., LL.D. This article is in the public domain

Public domain

Works are in the public domain if the intellectual property rights have expired, if the intellectual property rights are forfeited, or if they are not covered by intellectual property rights at all...

. The information contained herein, as such, may therefore be outdated.