Utica became a Roman colony under Hadrian, and the civitates liberae, municipia, castella, pagi and turres were peopled with Latins.
All three show the ordinary features of Roman castella, though they differ more than one would expect in forts built at one time by one general.
The army which guarded or coerced the province consisted, from the time of Hadrian onwards, of (I) three legions, the Second at Isca Silurum (Caerleon-on-Usk, q.v.), the Ninth at Eburacum (q.v.; now York), the Twentieth at Deva (q.v.; now Chester), a total of some 15,000 heavy infantry; and (2) a large but uncertain number of auxiliaries, troops of the second grade, organized in infantry cohorts or cavalry alae, each 500 or 1000 strong, and posted in castella nearer the frontiers than the legions.
The auxiliary castella were hardly a tenth of the size, varying generally from three to six acres according to the size of the regiment and the need for stabling.
The two territories designated respectively Nueva Andalucia and Castella de Oro were united in 1514 into the province of Tierra-firma, and entrusted to Pedro Arias de Avila.