Conversation so far:
What was the position of Horace Mann at the Antioch College ?
From September 1852 to Horace Mann's death, he served as President of Antioch College.
How did Horace Mann pass away ?
Horace Mann collapsed shortly after the 1859 commencement and died that summer.
Was Horace Mann ill ?
What else did Horace Mann do in his last years besides serving as President of Antioch College?
Horace Mann was nominated for governor of Massachusetts by the Free Soil Party, and the same day was chosen president of the newly established Antioch College at Yellow Springs, Ohio.

Question: What did he do in the Unitarian church ?
Self-contained rewrite: What did Horace Mann do in the Unitarian church ?