independent schools, commonly referred to as "public schools", included in the original Public Schools Act 1868. Following the public school tradition, Eton is a full boarding school, which means all pupils live at the school, and is one of five such remaining single-sex boys' public schools in the United Kingdom (the others being Harrow School, Radley College, Sherborne School and Winchester College) to continue this practice. It has educated 19 British Prime Ministers and generations of aristocracy, and has been referred to as the chief nurse of England's statesmen.