Alton first appeared in national history in the month of July 1101. When William Rufus died in 1100 one of his brothers became King Henry I of England. Another brother became Robert, Duke of Normandy. The two soon quarreled and Robert invaded England. In July 1101 the two sides made a treaty at Alton and Robert went back to Normandy.

By the late 13th century Alton had grown into a small market town. To us it would seem tiny, with a population of only a few hundred but settlements were very small in those days. In 1307 the king granted Alton the right to hold a fair. (In the Middle Ages fairs were like markets but they were held only once a year and they attracted buyers and sellers from a wide area). Through the centuries Alton was a busy little town and its main industry was weaving. In the Middle Ages many pilgrims passed through Alton on their way to Canterbury.