A more detailed description of football is given in Francis Willughby's Book of Sports, written in about 1660. This account is particularly noteworthy as he refers to football by its correct name and is the first to describe the following: goals and a pitch ("a close that has a gate at either end. The gates are called Goals"), tactics ("leaving some of their best players to guard the goal"), scoring ("they that can strike the ball through their opponents' goal first win") and the way teams were selected ("the players being equally divided according to their strength and nimbleness"). He is the first to describe a law of football: "They often break one another's shins when two meet and strike both together against the ball, and therefore there is a law that they must not strike higher than the ball". His account of the ball itself is also very informative: "They blow a strong bladder and tie the neck of it as fast as they can, and then put it into the skin of a bull's cod and sew it fast in". He adds: "The harder the ball is blown, the better it flies. They used to put quicksilver into it sometimes to keep it from lying still". His book includes the first (basic) diagram illustrating a football pitch. Willughby's link with the public school system was that he had studied at sutton coldfield school, was a student at Cambridge University and frequented the Bodleian library at Oxford university.