Why did Henry the 7th marry elizabeth of york?

Henry VII married his cousin Elizabeth of York. There were several reasons why he married her. One was because she had a better claim on the throne than he did being the daughter and neice of two previous Kings. Also he wanted the fighting between the Lancastrians and York's to stop and the best way was to marry her. Another reason was because he needed heirs to make sure that the Tudor line was sucessful.