Following the defeat of Somerled in 1164 at the Battle of Renfrew, Somerled's head was brought to the cathedral. In 1175 Pope Alexander III recognised Glasgow as ‘a special daughter’ of Rome, freeing the diocese from the supremacy of the Archbishop of York. Around the same time Bishop Jocelin was granted a charter by William I to establish Glasgow as a burgh of barony, but with the privileges of a royal burgh.[9] The king attributed the birth of his only son, Alexander, to the intercession of St Mungo.