Louis IX (25 April 1214 – 25 August 1270), commonly known as Saint Louis, was a Capetian King of France who reigned from 1226 until his death. Louis was crowned in Reims at the age of 12, following the death of his father Louis VIII the Lion, although his mother, Blanche of Castile, ruled the kingdom until he reached maturity. During Louis's childhood, Blanche dealt with the opposition of rebellious vassals and put an end to the Albigensian crusade which had started 20 years earlier.