In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Q: The Black Guard was what?, Context: In the 18th century, the Moroccan Sultan Moulay Ismail "the Bloodthirsty" (1672–1727) raised a corps of 150,000 black slaves, called his Black Guard, who coerced the country into submission.
A: 
a corps