The deaths of his cousins elevated Gemellus and his older cousin Gaius Caesar (Caligula). As there was no formal mechanism for succession of the imperial office, the only legal way in which Tiberius could promote an heir who was too young to assume the political powers of emperor was to bequeath to him his own estate upon which much of the Roman state had come to depend. According to Suetonius, Tiberius had suspicions of Gaius but he detested Gemellus as he believed him to be the result of an adulterous affair by his mother. Gemellus' young age was another factor in the advancement of Caligula, who was made quaestor in 33. The two were summoned by Tiberius to Capri in 35 where they were made joint-heirs to his estates. Tacitus records that while they were in Capri, Tiberius looked at Caligula in tears, with Gemellus in his arms, and told him: