Historically, Gainsborough is the "capital that never was." Towards the end of July 1013, the Dane Sweyn Forkbeard and his son and heir Cnut (Canute) arrived in Gainsborough with an army of conquest. Sweyn defeated the Anglo-Saxon opposition and King Ethelred fled the country. Sweyn was declared King of England and returned to Gainsborough. Sweyn and Cnut took up high office at the Gainsborough Castle on the site of the present-day Old Hall, while his army occupied the camp at Thonock (now known as Castle Hills). However, Sweyn died, or perhaps was killed five weeks later in Gainsborough. His son Cnut established a base elsewhere. So Gainsborough was named as capital of England and of Denmark for five weeks in the year 1013.