The Roman army of
the late Republic 88–30 BC marks the continued transition between the
conscription based citizen levy of the mid Republic and the mainly volunteer professional
standing forces of the imperial era. The main literary source for the army's organization
and tactics in this phase are the works of Julius Cesar the most notable of a series of warlords who
contested for power in this period. As a result of the Social War 91–88 BC all
Italians were granted Roman citizenship the old allied alae were abolished and their members integrated into the
legions. Regular annual conscription remained in force and continued to provide
the core of legionary recruitment but an ever increasing proportion of recruits
were volunteers who signed up for 16 year terms as opposed to the maximum 6
years for conscripts.
Information from http://www.bbc.co.uk/schools/primaryhistory/romans/the_roman_army/
