James Barry Munnik Hertzog (1866–1942) was a prominent South African general and politician. Born the same year that diamonds were discovered in Kimberley, which marked the start of South Africa's mineral revolution and the resultant protracted struggle between British and Afrikaner forces to control the Transvaal and Orange Free State republics, Hertzog's military and political career showcased the intense contestations over territorial sovereignty, ethnic and racial identity, and nationalism that were the hallmarks of South Africa's pre-apartheid history.
Hertzog formally entered politics in 1906, as co-founder of the Orangia Unie (Orangia Union) party in the Orange River Colony. Following the colony's grant of responsible self-government in November 1907, he became one of four cabinet members in its first (and only) government.
Hertzog first became prime minister of South Africa in 1924 as a result of his National Party's formation of a coalition government with the Labour Party.
Hertzog retired from politics in December 1940, after an attempt to reunify Afrikaner nationalists politically devolved into irreconcilable fighting over the National Party's stance on republicanism. The next year, his followers, led by Nicolaas Havenga, formed the Afrikaner Party.