As the son of a leading equestrian family, Aelius Seianus started his career with outstanding inherited opportunities and advanced to his well known pre-eminent position under Tiberius. He appears to have deliberately avoided the Senatorial career which must have been possible for him. This retention of equestrian status may not have been unusual as it appears to us, although Seianus was one of the first to realise the potential for political advancement without leaving the equestrian order. Other members of his immediate family had achieved consular standing, as is made clear by Velleius. Although in one contrast Tacitus is scathing about his background, and provides some of the scandal associated with his early career, it is far from clear that there existed any serious impediment to his transition to Senatorial status. In this paper I propose to investigate his background and why adoption did not automatically ensure his entry into the Senatorial order, as well as to analyse some of the family startegies involved in such adoptions.