This Aristobulus was probably the same person as the brother of Herod Agrippa I. Aristobulus belonged to the Roman ruling class and lived in Rome for many years before his death around AD 48 or 49 (see Josephus, Antiquities 18.8.4; War 2.11.6). The phrase the household of Aristobulus most likely refers to his family members and their servants who lived in Rome.