Augustus
Augustus (; 23 September 63 BC – 19 August AD 14) was a Roman statesman and military leader who was the first Emperor of the Roman Empire, controlling Imperial Rome from 27 BC until his death in AD 14. His status as the founder of the Roman Principate has consolidated an enduring legacy as one of the most effective and controversial leaders in human history.
Roman army
Under the founder–emperor Augustus (ruled 30 BC – 14 AD), the legions, c. 5,000-strong all-heavy infantry formations recruited from Roman citizens only, were transformed from a mixed conscript and volunteer corps serving an average of 10 years, to all-volunteer units of long-term professionals serving a standard 25-year term (conscription was only decreed in emergencies). In the later 1st century, the size of a legion's First Cohort was doubled, increasing legionary personnel to c. 5,500.