Kenneth O. May Prize and Medal in history of mathematics is an award of the International Commission on the History of Mathematics (ICHM) "for the encouragement and promotion of the history of mathematics internationally". It was established in 1989 and is named in honor of Kenneth O. May, the founder of ICHM. Since then, the award is given every four years, at the ICHM congress.
Kenneth O. May Prize winners
Source: (1989-2005) A Brief History of the Kenneth O. May Prize