Which tennis Grand Slam tournament was the last to be established?

The Grand Slam tournaments, also referred to as majors, are the world's four most important annual professional tennis events. The tournaments offer the most ranking points, prize money, public and media attention, the greatest strength and size of the field, and the longest matches for men (best of 5 sets).

The four Grand Slam tournaments are the Australian Open in January, the French Open from late May to early June, Wimbledon in late June to early July, and the US Open in August–September, with each played over two weeks. The Australian and the United States tournaments are played on hard courts, the French on clay, and Wimbledon on grass.

The Australian Open was the last of the four Grand Slam tournaments to be established. Wimbledon is the oldest tournament, founded in 1877, followed by the US in 1881, the French in 1891, and the Australian in 1905, but they were not all officially designated majors until 1925.