Acts 10:1 New English Translation

10 Now there was a man in Caesarea^[a] named Cornelius, a centurion^[b] of what was known as the Italian Cohort.^[c]

Acts 10:1 sn Caesarea was a city on the coast of Palestine south of Mount Carmel (not Caesarea Philippi). It was known as “Caesarea by the sea” (BDAG 499 s.v. Καισάρεια 2). Largely Gentile, it was a center of Roman administration and the location of many of Herod the Great’s building projects (Josephus, Ant. 15.9.6 [15.331-341]).
Acts 10:1 sn A centurion was a noncommissioned officer in the Roman army or one of the auxiliary territorial armies, commanding a centuria of (nominally) 100 men. The responsibilities of centurions were broadly similar to modern junior officers, but there was a wide gap in social status between them and officers, and relatively few were promoted beyond the rank of senior centurion. The Roman troops stationed in Judea were auxiliaries, who would normally be rewarded with Roman citizenship after 25 years of service. Some of the centurions throughout the region may have served originally in the Roman legions (regular army) and thus gained their citizenship at enlistment. Others may have inherited it, like the apostle Paul did (cf. Acts 22:28).
Acts 10:1 sn A cohort was a Roman military unit of about 600 soldiers, one-tenth of a legion (BDAG 936 s.v. σπεῖρα). The Italian Cohort has been identified as cohors II Italica which is known to have been stationed in Syria in a.d. 88.

New English Translation (NET)