Conversation so far:
Where did Camille Saint-Saëns begin his early career?
On leaving the Conservatoire in 1853, Camille Saint-Saëns accepted the post of organist at the ancient Parisian church of Saint-Merri near the Hôtel de Ville.
How long did Camille Saint-Saëns hold the post of organist at the Parisian church?
In early 1858 Camille Saint-Saëns moved from Saint-Merri to the high-profile post of organist of La Madeleine, the official church of the Empire.

Question: What else did he do?
Self-contained rewrite: What else did Camille Saint-Saëns do in addition to becoming a high-profile post of organist?