Great Trek: Battle of Blood River: Voortrekkers led by Andries Pretorius and Sarel Cilliers defeat Zulu impis, led by Dambuza (Nzobo) and Ndlela kaSompisi in what is today KwaZulu-Natal, South Africa.

The Great Trek was a northward migration of Dutch-speaking settlers who travelled by wagon trains from the Cape Colony into the interior of modern South Africa from 1836 onwards, seeking to live beyond the Cape's British colonial administration. The Great Trek resulted from the culmination of tensions between rural descendants of the Cape's original European settlers, known collectively as Boers, and the British. It was also reflective of an increasingly common trend among individual Boer communities to pursue an isolationist and semi-nomadic lifestyle away from the developing administrative complexities in Cape Town. Boers who took part in the Great Trek identified themselves as voortrekkers, meaning "pioneers" or "pathfinders" in Dutch and Afrikaans.

The Battle of Blood River or Voortrekker-Zulu War was fought on the bank of the Ncome River, in what is today KwaZulu-Natal, South Africa between 464 Voortrekkers ("Pioneers"), led by Andries Pretorius, and an estimated 25,000 to 30,000 Zulu. Estimations of casualties amounted to over 3,000 of King Dingane's soldiers dead, including two Zulu princes competing with Prince Mpande for the Zulu throne. Three Voortrekker commando members were lightly wounded, including Pretorius.

The year 1838 was the most difficult period for the Voortrekkers from when they left the Cape Colony, till the end of the Great Trek. They faced many difficulties and much bloodshed before they found freedom and a safe homeland in their Republic of Natalia. This was only achieved after defeating the Zulu Kingdom, at the Battle of Blood River, which took place on Sunday 16 December 1838. This battle would not have taken place if the Zulu King had honoured the agreement that he had made with the Voortrekkers to live together peacefully. The Zulu king knew that they outnumbered the Voortrekkers and decided to overthrow them and that led to the Battle of Blood River.

Andries Wilhelmus Jacobus Pretorius was a leader of the Boers who was instrumental in the creation of the South African Republic, as well as the earlier but short-lived Natalia Republic, in present-day South Africa. The large city of Pretoria, executive capital of South Africa, is named after him.