Ala (Roman allied military unit)

An ala (Latin for "wing"; pl. alae) was the term used during the middle of the Roman Republic (338–88 BC) to denote a military formation composed of conscripts from the socii, Rome's Italian military allies. A normal consular army during the period consisted of two legions, composed of only Roman citizens, and two allied alae.

The alae were somewhat larger than normal legions, 5,400 or 5,100 men against the legion's 4,500 men, and it contained a greater quantity of cavalry, usually 900 horsemen against the 300 supplied by the Romans.

From the time of the first Roman emperor, Augustus (ruled 27 BC – AD 14), the term ala was used in the professional imperial army to denote a much smaller (c. 500), purely cavalry unit of the non-citizen auxilia corps: see ala (Roman cavalry unit).