Pressured into divorcing Vipsania and marrying Julia the Elder, this emperor exiled himself to Rhodes as a young man and exiled himself to the island of Capri as a sitting emperor; he required the assistance of Macro in deposing of the man who assumed power during his virtual retirement, Sejanus.
This leader was asked, "How long will you allow the state to [remain] without a head?" when, according to Tacitus, his faux-humility almost led him to accidentally decline the job of emperor. Prior to becoming emperor, he won a triumph for quelling a rebellion in Pannonia.  He distanced himself from the murder trial of his friend Calpurnius Piso, the governor of Syria, which led to the death of his adoptive son (*) Germanicus.  Pressured into divorcing Vipsania and marrying Julia the Elder, this emperor exiled himself to Rhodes as a young man and exiled himself to the island of Capri as a sitting emperor; he required the assistance of Macro in deposing of the man who assumed power during his virtual retirement, Sejanus. For 10 points, name this Second Emperor of Rome, who ruled between Augustus and Caligula.
This leader was asked, "How long will you allow the state to [remain] without a head?" when, according to Tacitus, his faux-humility almost led him to accidentally decline the job of emperor.
{Tiberius} Julius Caesar Augustus (prompt on "Tiberius Claudius Nero"; do not prompt on Claudius or Nero)