The twentieth century saw the greatest development of heraldry in South Africa, partly as a result of political and constitutional changes.
In 1911 the king granted each provincial administration its own arms, but none of them was ever used. The Cape, Natal and OFS continued to use their old colonial arms, and the Transvaal had no official emblem.
British grants of arms continued, especially to recently-knighted politicians and mining magnates. The pace slowed down in the mid-1920s, perhaps because the first Afrikaner nationalist government (1924-33) stopped the granting of titles and knighthoods.
In 1923, the defence force introduced helmet flashes which, half a century later, were to form the basis of many army unit coats of arms.
In 1928, the government introduced an orange, white and blue national flag, to be flown alongside the Union Jack. A new artistic rendition of the national arms was introduced in 1930, and an "embellished version" was approved and recorded in 1932. From the 1930s, the protea was accepted as the national flower emblem, though it was not formally proclaimed as such until the 1960s.
An early heraldic publication was South African Coats of Arms (c1929), a cigarette card album of municipal arms and pseudo-arms.
The rising tide of Afrikaner nationalism and republicanism which began in the early 1930s had an effect on heraldry. Several books and magazine articles on Afrikaner family history were published during the 1930s and '40s. They were illustrated with arms which, reportedly, many people assumed - alas, as later research showed, many were fictitious, or actually belonged to other families.
In another sign of the times, the Orange Free State provincial administration revived the old OFS republican arms as its provincial arms in 1937.
World War II (1939-45) saw further development in the field of military heraldry. The land forces introduced divisional patches, the air force introduced squadron emblems and unit badges, and a few naval vessels adopted ships' badges. After the war, the defence forces adopted Royal Navy and Royal Air Force models for navy and air force insignia.
An Afrikaner nationalist government came to power in 1948, and entrenched itself in office for nearly half a century. A republic was high on its agenda, and between 1948 and 1961 it systematically broke down the British connection. In 1951, the Transvaal revived the old South African Republic arms as provincial arms.
Despite (or perhaps, because of) the breaking down of the British connection, the late 1940s and the '50s saw more English and Scottish grants of arms to South Africans than ever before: at least three dozen arms, nearly half of them municipal.
Standards began to improve in the 1950s. The Heraldry Society of SA was formed in 1953. The defence force established its own heraldic office in 1954, and in 1956 an official committee under Prof Adriaan Pelzer recommended setting up a central heraldic authority on the Swedish model. The body of heraldic literature began to grow, particularly through the efforts of Dutch heraldist Cornelis Pama, who settled in South Africa in 1955 and dominated the scene for nearly forty years.
The crown and the Union Jack were abolished as official symbols in 1957.
South Africa became a republic, and left the Commonwealth, in 1961. The national arms and flag were retained unchanged, and official insignia were introduced for the new state president.