One of the most infamous events of Olympic history occurred under the rule of Nero. He desired victory in all chariot races of the Panhellenic Games in a single year, so he ordered the four main hosts to hold their games in 67 and therefore the scheduled Olympics of 65 were postponed. At Olympia he was thrown from his chariot, but still claimed victory. Nero also considered himself a talented musician, so he added contests in music and singing to those festivals that lacked them, including the Olympics. Despite his terrible singing, he won all the contests, no doubt because judges were afraid to award victory to anyone else. After his assassination, the Olympic judges had to repay the bribes he had bestowed and declared the “Neronian Olympiad” to be void.
Source: Wikipedia