Henry II appointed his friend Thomas Becket as Archbishop of Canterbury. However, their friendship soured when Becket refused to help Henry reform the church courts to be under the king's authority. Tensions escalated and Becket fled to France. Upon returning to England, Becket excommunicated Henry's supporters, angering the king. Four knights heard Henry's angry words "Who will rid me of this troublesome priest?" and took it upon themselves to murder Becket in Canterbury Cathedral. Henry later claimed he did not intend for Becket to be killed.