Carlisle is in the City of Carlisle, a district of Cumbria in North West England. It is located at the confluence of the rivers Eden, Caldew and Petteril, 10 miles (16 km) south of the Scottish border. It is the largest settlement in the county of Cumbria, and serves as the administrative centre for both Carlise City Council and Cumbria County Council. At the time of the 2001 census, the population of Carlisle was 71,773, with 100,734 living in the wider district. Historically the county town of Cumberland, the early history of Carlisle is marked by its status as a Roman settlement, established to serve the forts on Hadrian's Wall. During the Middle Ages, because of its proximity to the Kingdom of Scotland, Carlisle became an important military stronghold; Carlisle Castle, still relatively intact, was built in 1092 by William Rufus, and having once served as a prison for Mary, Queen of Scots. The castle now houses the Duke of Lancaster's Regiment and the Border Regiment Museum. In the early 12th century Henry I allowed the foundation of a priory in Carlisle. The town gained the status of a diocese in 1122, and the priory became Carlisle Cathedral.