Lewis & Short

con-cŏmĭtor, ātus, āri, 1, v. dep., to attend, accompany (late Lat., except in part. perf., v. infra): concomitando tuos, Ven. Carm. 8, 7, 183: Astris Caesario concomitante suo, id. ib. 8, 6, 157.
Part. perf. in pass. sense: * concŏmĭtātus, a, um, accompanied: quibus concomitata, Plaut. Mil. 4, 3, 10 Brix ad loc.