 Complete the following phrase:  Between 1996 and 1999, OSullivan reached three world semi-finals in four years. At the 1997 World Championship, he achieved his first maximum break in professional competition; compiled in a time of 5 minutes and 8 seconds, it remains the fastest competitive maximum break in snooker history. He won his second UK title later that year at the 1997 UK Championship. Despite these successes, his career also became marred by controversy in the later 1990s. During the 