Saint Louis IX was crowned King of France at age 12 and reigned until his death. His mother ruled the kingdom until he reached maturity and instructed him in his education and religion. Louis married Margaret of Provence in 1234 and they had 11 children. He saw himself as a “Lieutenant of God on earth” even obtaining Christ's crown of thorns from Baldwin II, Latin emperor at Constantinople. He was an exemplary king, protecting the poor and clergy, founding hospitals and the Abbey of Royaumount and built Saint-Chapelle, an architectural gem. He led two crusades in 1238 and 1267, where he died of the plague.