Conversation so far:
How old was Richard Francis Burton when he went on his first exploration?
Richard Francis Burton was about 32.
Why did Richard Francis Burton go to Mecca?
Richard Francis Burton had planned it whilst travelling disguised among the Muslims of Sindh, and had laboriously prepared for the adventure by study and practice.

Question: What did he do in 1851?
Self-contained rewrite: What did Richard Francis Burton do in 1851?