Claudius
The attempted coup d'état by Silius and Messalina had probably made Claudius realize the weakness of his position since he did not have an obvious adult heir, Britannicus being just a boy. Agrippina's son Lucius Domitius Ahenobarbus (the emperor Nero) was one of the last males of the imperial family. Future coup attempts could rally around the pair, and Agrippina was already showing such ambition. In any case, Claudius accepted Agrippina, and later adopted the newly mature Nero as his son.