Antoninus Pius "adopted son"

Antoninus Pius acquired much favor with Hadrian, who adopted him as his son and successor on 25 February 138, after the death of his first adopted son Lucius Aelius, on the condition that Antoninus would, in turn, adopt Marcus Annius Verus, the son of his wife's brother, and Lucius, son of Lucius Aelius, who afterward became the emperors, Marcus Aurelius and Lucius Verus.