An Idea is Born
The idea for the PGA Championship was conceived of during a meeting in January 1916. That day, 35 golf professionals met to discuss their ideas for building an organization that became The Professional Golfers' Association of America. Attendees decided a national golf championship should be held each year. The host of the meeting, a golfer and businessman named Rodman Wanamaker, provided the trophy for the event--the Wanamaker Cup, which still exists today--as well as the first purse, which was $2,580.
The Early Days
The first PGA Championship was held in 1916. Jim Barnes of England won the inaugural event, as well as the second championship, held at the Engineers Country Club in Roslyn Harbor, New York. There was no PGA Championship during World War I in 1917 or 1918. The first time the tournament was held outside of New York was in 1920, when it was played at the Flossmoor Country Club in Flossmoor, Illinois. The PGA Championship was a match-play event until 1958, when it changed to stroke play.
The PGA of America, an organization made up primarily of club and teaching professionals, runs the PGA Championship. The organization created the event to provide a high-profile tournament specifically for professional golfers, not amateurs. As a result, the vast majority of golfers who compete each year in the tournament are professionals. Leading amateurs never have been invited to participate in the PGA Championship, and the only way they can gain an invitation is by winning one of the other three major championships, which generally include a small number of amateurs in their fields.
Winners of the PGA Championship
Many of the most notable names in golf have won the PGA Championship, including Walter Hagen, Byron Nelson, Ben Hogan, Jack Nicklaus, and Tiger Woods. A full list of champions is available here: List of PGA Championship Winners.