Conisbrough Castle has its origins in the years following the Norman Conquest. It was founded in the late 11th century by William de Warenne, a trusted supporter of William the Conqueror. The castle was built in a commanding position on a limestone ridge above the River Don. Its earliest form was a motte-and-bailey structure, later rebuilt in stone. The most famous feature, the tall circular keep, was added in the 12th century and remains one of the best-preserved examples of Norman architecture in England.

Throughout the Middle Ages, the castle was a symbol of wealth and authority. It was home to important noble families, including the de Warenne family and the Earls of Lancaster. While the castle was never the site of major battles, it played an important role in local governance and defence. Over time, its importance declined. By the 1500s, the castle was no longer used as a residence, and its buildings gradually fell into ruin. Stones were taken for building nearby, and the once grand fortress became a romantic ruin.

Even in its ruined state, the keep survived almost completely intact. Its unusual design, with thick walls and six buttresses, continues to attract interest from historians and visitors. In the 19th century, the castle inspired Sir Walter Scott, who featured it in his novel Ivanhoe, bringing it to the attention of a wider public. Today, Conisbrough Castle is cared for by English Heritage. Visitors can enjoy impressive views, learn about medieval life, and explore a rare piece of Norman history in a peaceful South Yorkshire setting.