 Arrecinus Clemens was born into an equestrian family from Pisaurum, being the homonymous son of Emperor Gaius' Praetorian Prefect.Clemens' sister was Arrecina Tertulla, the first wife of the future Emperor Titus.Despite being a member of the Senate, he was placed at the head of the Praetorian Guard in 70 by Vespasian's political ally, Gaius Licinius Mucianus, amidst concerns that the current commander, Arrius Varus, was growing too politically influential.