The increased military efficiency led to more and more clans being incorporated into Shaka's Zulu empire, while other tribes moved away to be out of range of Shaka's impis. The ripple effect caused by these mass migrations, known as the difanqane, had effects as far away as present-day Zimbabwe, where local Ndebele people can claim their descent to refugees from Shaka's state-sponsored terror. The demoralised state of many such refugee clans undoubtedly made them easy for both the British and the Voortrekkers to subjugate, and thus indirectly advanced the cause of colonialism.
Although Shaka made preliminary contacts with Europeans from the British Empire, he was killed by his brother Dingane before he could test his strategic brilliance against an army equipped with flintlock muskets. His successors got plenty such opportunities, both against the Voortrekkers and against British forces. Later in the 19th century the Zulus would be one of the few African peoples who managed to defeat the British Army.