Shortly afterward, the head of the Praetorian Guard, Macro, tells Caligula that Tiberius demands his immediate presence at Capri, where the Emperor lives with his close friend Nerva, a dim-witted relative Claudius, and Caligula's adopted son (Tiberius’s grandson) Gemellus. Fearing assassination, Caligula is afraid to leave but his sister and lover Drusilla persuades him to go. At Capri, Caligula finds that Tiberius has become depraved, showing signs of advanced venereal diseases, and embittered with Rome and politics. Tiberius enjoys swimming with naked youths and watching degrading sex shows that include deformed people and animals. Caligula observes with fascination and horror. Tensions rise when Tiberius tries to poison Caligula in front of Gemellus. Nerva commits suicide and Caligula tries to kill Tiberius but loses his nerve. Proving his loyalty to Caligula, Macro kills Tiberius instead with Gemellus as a witness. After Tiberius' death and burial, Caligula is proclaimed the new Emperor, then proclaims Drusilla as his equal, to the apparent disgust of the Roman Senate. Drusilla, fearful of Macro's influence, persuades Caligula to get rid of him. Caligula sets up a mock trial in which Gemellus is intimidated into testifying that Macro murdered Tiberius, then has Macro's wife Ennia banished from Rome. After Macro is executed in a gruesome public game, Caligula appoints Tiberius' former adviser Longinus as his personal assistant while pronouncing the docile Senator Chaerea as the new head of the Praetorian Guard. Drusilla tries to find Caligula a wife among the priestesses of the goddess Isis, the cult they secretly practice. Caligula wants to marry Drusilla, but she insists they cannot marry because she is his sister. Instead, Caligula marries Caesonia, a priestess and notorious courtesan, after she bears him an heir. Drusilla reluctantly supports their marriage. Meanwhile, despite Caligula's popularity with the masses, the Senate expresses disapproval for what initially seem to be light eccentricities. Darker aspects of Caligula's personality emerge when he rapes a bride and groom on their wedding day in a minor fit of jealousy and orders Gemellus's execution to provoke a reaction from Drusilla.