Warwick Castle is situated in the town of Warwick, on a sandstone bluff at a bend of the River Avon. The river, which runs below the castle on the east side, has eroded the rock the castle stands on, forming a cliff. The river and cliff form natural defences. When construction began in 1068, four houses belonging to the Abbot of Coventry were demolished to provide room. The castle's position made it strategically important in safeguarding the Midlands against rebellion.