Hendon, famous for its aerodrome and police college, was an ancient and large manor and parish. Before that it was a Roman settlement with Watling Street forming much of its western boundary. In the Middle Ages it was a Westminster Abbey manor recorded in Domesday Book. It was an area of small hamlets scattered among woodland which was gradually cleared for the production of hay for the London horse population. The first real signs of growth, however, came not with the aerodrome but with the extension of the Underground Railway, which brought really rapid change.