Prior to 1902, the prime minister sometimes came from the House of Lords, provided that his government could form a majority in the Commons. However as the power of the aristocracy waned during the 19th century the convention developed that the prime minister should always sit as a Member of Parliament in the lower house, making them answerable only to the Commons in Parliament. As leader of the House of Commons, the prime minister's authority was further enhanced by the Parliament Act 1911 which marginalised the influence of the House of Lords in the law-making process.