In South African history, the Battle of Blood River was fought on 16 December 1838.
The Voortrekkers, led by Andries Pretorius, defended a laager (circle of ox wagons) against Zulu impis under King Dingane.
Before the battle commenced the Voortrekkers made a vow to God that, should they be delivered, they would commemorate the day as a Sabbath and build a church.
Of the 464 Voortrekkers defending the laager against the Zulu forces numbering in the 20,000 warriorsonly three were wounded, none perished.
The 16th December is a public holiday in South Africa. Pre-1994 it was called the Day of the Vow, today it is known as the Day of Reconciliation.