The Royal College of St. Peter in Westminster, better known as Westminster School and standing in the precincts of Westminster Abbey in London, is one of Britain's independent schools, with the highest Oxford and Cambridge acceptance rates of any secondary school or college in Britain. With a history going back to the 11th century, the school's notable alumni include Ben Jonson, Robert Hooke, Christopher Wren, John Locke, Jeremy Bentham, Edward Gibbon, Henry Mayhew, A. A. Milne, Tony Benn and seven Prime Ministers. The school traditionally encourages independent and individual thinking. Boys are admitted to the Under School at age seven, and to the senior school at age thirteen; girls are admitted only at sixteen. The school has around 750 pupils; around a quarter are boarders, most of whom go home at weekends, after Saturday morning school. It is one of the original nine British public schools (the so-called 'Clarendon Schools') as defined by the Public Schools Act 1868.