Input (grade 12): The elder Pretorius had become a national hero of the Voortrekkers after his victory over the Zulus in the Battle of Blood River. Andries Pretorius also negotiated the Sand River Convention (1852), in which Britain acknowledged the independence of the Transvaal.
Output (grade 8): Andries Pretorius had become a hero of the Voortrekkers after the Battle of Blood River.