A ruined castle dominates the sloping banks of the Tees and overlooks the town that has developed at its feet. It was built in the early 11C, on land offered by William II to the Baliol family, founders of Baliol College in Oxford in 1263 and Sweetheart Abbey in Scotland. The castle was arranged around four courtyards. Today, Baliol Tower (c. 1250) is the best preserved reminder of this once massive building.