The Voortrekker Monument is a monument in the city of Pretoria, South Africa. The massive granite structure, built to honour the Voortrekkers who left the Cape Colony between 1835 and 1854, was designed by the architect Gerard Moerdijk who had the idea to design a "monument that would stand a thousand years to describe the history and the meaning of the Great Trek to its descendants". It can be seen from almost any location in the city, as it is seated on a hilltop.
Sarel Cilliers was a Voortrekker leader and a preacher. With Andries Pretorius, he led the Boers to a huge victory over the Zulus at the Battle of Blood River in 1838. In particular, Cilliers lead the Voortrekkers in a vow which promised that if God would protect them and deliver the enemy into their hands, they would build a church and commemorate the day of their victory as if it were an annual Sabbath day, which their descendants would also be instructed to honour on every 16/12.
Most state in western and central Africa were unstable. Wars elevated the importance of the military and promoted slave trade. Centralization and hierarchy developed in the enslaving societies. Europeans along the western coast caused a shift of power. Inland states close to the coast were free from direct European influence but became intermediaries in the trade of slaves due to Western firearms and other goods.