Rebecca Mead in The New Yorker:
Nero, who was enthroned in Rome in 54 A.D., at the age of sixteen, and went on to rule for nearly a decade and a half, developed a reputation for tyranny, murderous cruelty, and decadence that has survived for nearly two thousand years. According to various Roman historians, he commissioned the assassination of Agrippina the Younger—his mother and sometime lover. He sought to poison her, then to have her crushed by a falling ceiling or drowned in a self-sinking boat, before ultimately having her murder disguised as a suicide. Nero was betrothed at eleven and married at fifteen, to his adoptive stepsister, Claudia Octavia, the daughter of the emperor Claudius. At the age of twenty-four, Nero divorced her, banished her, ordered her bound with her wrists slit, and had her suffocated in a steam bath. He received her decapitated head when it was delivered to his court. He also murdered his second wife, the noblewoman Poppaea Sabina, by kicking her in the belly while she was pregnant.
Nero’s profligacy went beyond slaughtering his nearest and dearest. He spent a fortune building an ornate palace, only to have it burn down, along with the rest of the city of Rome, in a conflagration that lasted for more than a week. Nero watched the destruction from a safe elevation, singing of the decimation of Troy. He was famous for never wearing the same garment twice. He sought out sexual thrills like a hog snuffling for truffles. He had a favored freedman, Sporus, castrated, then married him in a ceremony in which Sporus was dressed in the traditional garb of a bride and Nero played the groom. Later, Nero repeated the ceremony with another of his freedmen playing the groom while he adopted the role of bride, sans castration; the pseudo-nuptials were consummated on a couch in full view of guests at a banquet. He was attention-seeking, petulant, arbitrary. He had the senator Publius Clodius Thrasea Paetus murdered on the ground that his expressions were overly melancholic.
More here.