Republic Day; South Africa; May 31; Also called Union Day. On May 31, 1961, the Republic of South Africa was established, severing its ties to the British Commonwealth. Also, on May 31, 1910, the Union of South Africa was established, uniting the various South African colonies. And May 31, 1902, was the formal ending of the Boer War, which began on Oct. 12, 1899.
