The British constitution comprises multiple documents. The written part consists of the Magna Carta, written in 1215; the Petition of Right, passed by Parliament in 1628; and the Bill of Rights of 1689. It also includes the entire body of laws enacted by Parliament, precedents established by decisions made in British courts of law, and various traditions and customs. The democratically elected House of Commons can alter these laws with a majority vote. The constitution continually evolves as new laws are passed and judicial decisions are handed down. All laws passed by Parliament are regarded as constitutional, and changes or amendments to the constitution occur whenever new legislation overrides existing law. Although the Crown gives its royal assent to legislation, this is a mere formality.