Between 24 July and 26 October 2008 a large exhibition was held in the British Museum in London with the title Hadrian: Empire and Conflict . It was the exhibition to give us the idea of reflecting on how Hadrian was adopted by Trajan. Trajan’s wife the Empress Plotina backed Hadrian’s career in every respect. Referring to Hadrian it is more appropriate to use the word adrogatio . The present study draws attention to the word vesticeps as used in Gellius’ work. (Gellius, Noctes Atticae 5. 19). Starting from the etymology of the word it can be claimed that adrogatio could only happen after putting on the toga virilis . It was one of the conditions of adrogatio that the adrogator had to be at least 60 years old. Trajan reached that age in 113, so the adoption could not happen before that. Hadrian had been considered to be Trajan’s successor since he became a legatus in Syria, so the takeover of power was not a result of court conspiracy.