which he also refused. If either of them were allowed to remarry it would have threatened the line of succession that Tiberius was comfortable with. By refusing Sejanus' request, Tiberius made it clear he was content with the children of Germanicus and his own grandchildren being his successors. Had Sejanus married Livilla, their children would have provided another line of possible successors. The implication of Agrippina's request was that she needed a man from outside the imperial family to serve as protector and step-father of possible imperial heirs, a powerful position. It was also an implied reprimand: Tiberius was meant to be the guardian of the imperial family. Tiberius was in a tough position. He was faced with a conflict between his family and his friend. His solution was surprising. In AD 26, he left Rome altogether and retired to the island of Capri in the Bay of Naples. He cut himself off from the factions altogether and abandoned politics. He left Rome in the care of Sejanus. This allowed Sejanus to freely attack his rivals. Downfall With Tiberius away from Rome, the city would see a rise of politically motivated trials on the part of Sejanus and his supporters against Agrippina and her associates. Many of her friends and associates were subsequently accused of maiestas ("treason") by the growing number of accusers. It was also common to see charges of sexual misconduct and corruption. In AD 27, Agrippina found herself placed under house arrest in her suburban villa outside Herculaneum. In AD 28, the Senate voted that altars to Clementia (mercy) and Amicitia (friendship) be raised. At that time, Clementia was considered a virtue of the ruling class, for only the powerful could give clemency. The altar of Amicitia was flanked by statues of Sejanus and Tiberius. By this time, his association with Tiberius was such that there were those in Roman society who erected statues in his honor and gave prayers and sacrifices in his honor. Sejanus' birthday was honored as if he were a member of the imperial family. According to Richard Alston, "Sejanus' association with Tiberius must have at least indicated to the people that he would be further elevated." Sejanus did not begin his final attack on Agrippina until after the death of Livia in AD 29. Tacitus reports a letter being sent to the Senate from Tiberius denouncing Agrippina for her arrogance and prideful