in 26, tiberius moved from rome to the isle of capri, and left administration largely in the hands of his unscrupulous praetorian prefect sejanus. sejanus became the effective ruler of rome, and plotted against tiberius, murdering people who opposed him. when alerted, tiberius counter-plotted to remove sejanus from his official positions, and eventually executed him. more executions followed of people who had committed crimes under sejanus' rule.