Michael Phelps will try to break an ancient Olympic record this week. The swimmer has won 21 Olympic gold medals, 12 of them in individual events—and those dozen personal medals mean Phelps has tied an Olympic record that had been held for 2,168 years, Deadspin reports. Olympic historian Bill Mallon was first to report that Phelps had tied the record held by Leonidas of Rhodes, a sprinter who won multiple events at the 154th Olympiad in 164 BCE, and then at the next three Games, ultimately winning 12 individual titles. But, as Deadspin notes, he got wreaths instead of medals to mark his victories. Phelps could potentially overtake Leonidas: He competes in the 200m individual medley Thursday and the 100m butterfly Friday. (Check out this picture of 9-year-old Katie Ledecky getting Phelps' autograph a decade ago.)