Possible Clues:

• Catholic Church head
• Sailor you once left for a poet
• Tiara-wearing man who's not entirely comfortable with homosexuality
• Religious leader as father figure, ultimately
• Poet has work displayed in gym
• Poet inclined to pontificate?
• Pius I, e.g.
• Source of infallible teachings
• Writer who popularized the saying 'To err is human, to forgive divine'
• ''Fools rush in'' source