Fornsigtuna’s Iron Age royal manor house and other buildings on the site were torn down shortly before AD 1000, and the place-name Sigtuna was transferred to the newly-established Christian town. From then on, the Fornsigtuna estate was cultivated by a royal bailiff and tenant farmers, occupying a new site with a cross-marked runic stone on display. Ruins of a medieval manor at Fornsigtuna are men-tioned by a few 17th-century writers. Up to now the search for this building has been inconclusive but its existence should not be ruled out until further investigations have been conducted.