When Theobald died in 1161, Henry appointed Becket as Archbishop of Canterbury. Becket turned himself from a pleasure-seeking courtier to a solemn, plain-clothed preacher. On December 29, 1170, four knights assaulted and assassinated Becket in Canterbury Cathedral, believing the king wanted Becket out of the way. In fact, the murder resulted in Becket being declared a saint. Canterbury Cathedral is one of the largest and most beautiful churches in England. It was built between 1081 and 1138 by Archbishop Thurstan on the orders of King Cnut. The cathedral has been described as "the finest example of Norman architecture in Britain." The assassination of Becket brought about the end of the reign of Henry II. As well as being an incompetent ruler, he had become very unpopular because of his marriage to Eleanor of Aquitaine. Citizens across England were outraged that someone who wasn't royalty should have authority over them. They didn't feel like they had a voice in lawmaking or governance so they did what anyone would do today: they protested outside parliament and refused to pay their taxes. This led to more violence and the start of the War of the Roses. Within three years of Becket's death, there was fighting all over England between supporters of Theobald and those of Henry II. The war ended with the Battle of St. Albans in 1455 and Theobald was finally overthrown.