The earliest known castle in Kimbolton, a wooden motte and bailey castle, dating from Norman times, was not on the present site. All that remains of the Norman castle is a low mound, surrounded by a ditch and covered with trees, which can be seen by looking up the hill from the Duchess Walk.

Around 1200, the local Lord of the Manor was Geoffrey Fitzpiers, Earl of Essex. He was given permission by King John to hold a fair and market in historic Kimbolton, (the origin of the modern Statute Fair). The High Street was laid out as a market place, with the existing church at one end and a new castle, (probably a fortified manor house), at the other, on the site of the present castle. Nothing of this early castle has survived.

 

The Castle changed hands several times, and in the mid-15th century extensive building work on the inner courtyard was carried out for Ann Stafford, widow of the Duke of Buckingham. The historic Tudor Castle would later be home to Katharine of Aragon in her final days (see 1500-1700)