	The town developed on the River Colne on land belonging to St Albans Abbey until the 16th century. During the 12th century a charter was granted allowing a market, and the building of St Mary's Church began. The town grew partly due to travellers going to Berkhamsted Castle and the royal palace at Kings Langley. A mansion was built at Cassiobury in the 16th century. This was partly rebuilt in the 17th century and another country house was built at The Grove.