acts 28:16 And when we came to Rome, the centurion delivered the prisoners to the captain of the guard: but Paul was suffered to dwell by himself with a soldier that kept him. - Free Bible Online

      16. when we came to Rome--the renowned capital of the ancient world, situated on the Tiber.
      the centurion delivered the prisoners to the captain of the guard--the Prætorian Prefect, to whose custody, as commander of the Prætorian guard, the highest military authority in the city, were committed all who were to come before the emperor for trial. Ordinarily there were two such prefects; but from A.D. 51 to 62, one distinguished general--Burrus Aframus, who had been Nero's tutor--held that office; and as our historian speaks of "the captain," as if there were but one, it is thought that this fixes the apostle's arrival at Rome to be not later than the year 62 [WIES]. But even though there had been two when Paul arrived, he would be committed only to one of them, who would be "the captain" who got charge of him. (At most, therefore, this can furnish no more than confirmation to the chronological evidence otherwise obtained).
      but Paul was suffered to dwell by himself with a--"the"
      soldier that kept him--"guarded" him. (See on Ac 12:6). This privilege was allowed in the case of the better class of prisoners, not accused of any flagrant offense, on finding security--which in Paul's case would not be difficult among the Christians. The extension of this privilege to the apostle may have been due to the terms in which Festus wrote about him; but far more probably it was owing to the high terms in which Julius spoke of him, and his express intercession in his behalf. It was overruled, however, for giving the fullest scope to the labors of the apostle compatible with confinement at all. As the soldiers who kept him were relieved periodically, he would thus make the personal acquaintance of a great number of the Prætorian guard; and if he had to appear before the Prefect from time to time, the truth might thus penetrate to those who surrounded the emperor, as we learn, from Php 1:12, 13, that it did.

JFB.