Conversation so far:
Who captured Zheng He?
the Ming armies at Yunnan
When was Zheng He captured by the ming armies at yunnan?
in 1381
Why was Zheng He captured by the ming armies at yunnan in 1381?
General Fu took him prisoner.
How old was Zheng He when captured by General Fu?
Zheng He Was 10 years old

Question: What did they do to him while in captivity?
Self-contained rewrite: What did the ming armies do to Zheng He  while in captivity?