Whose ancient Olympic record of 12 individual titles did Phelps break in 2016?

Whose ancient Olympic record of 12 individual titles did Phelps break in 2016? Leonidas of Rhodes.

Leonidas was an elite runner from Rhodes who dominated the ancient Olympic Games in the second century BCE. Across four consecutive Olympiads, traditionally dated 164, 160, 156 and 152 BCE, he won the stadion, diaulos and hoplitodromos—the short footrace, longer footrace and armored race—12 times in total.

That record stood for more than two millennia. Phelps equaled it when he won his 12th individual Olympic gold in Rio, then moved ahead with his victory in the 200-meter individual medley, giving him 13 individual titles. The achievement concerned individual victories, not total medals: Phelps also accumulated numerous relay golds.

A common mix-up is confusing this Leonidas with Leonidas I, the Spartan king associated with Thermopylae. They were different historical figures. Leonidas of Rhodes was an ancient sporting champion, while the Spartan king lived centuries earlier and was known primarily as a military leader.