Heathen Army", captured York, unopposed due to conflict in the Kingdom of Northumbria. The next year they held the city when the Northumbrians tried to retake it; the army left the same year putting a local puppet king in charge of York and the area around York they controlled. The army returned in 875 and its leader Halfdan took control of York. From York, Viking kings ruled an area, known to historians as "The Kingdom of Jorvik", with Danes migrating and settling in large numbers in the Kingdom and in York. In York the Old Norse placename Konungsgurtha, Kings Court, recorded in the late 14th century in relation to an area immediately outside the site of the porta principalis sinistra, the west gatehouse of the Roman encampment, perpetuated today as King's Square, perhaps indicates a Viking royal palace site based on the remains of the east gate of the Roman fortress. In 954 the last Viking king, Eric Bloodaxe, was expelled and his kingdom was incorporated in the newly consolidated Anglo-Saxon state. A renowned scholar of this era was Wulfstan II, Archbishop of York. Several churches were built in York during the Viking Age including St Olave's, built before 1055 on Marygate, which is dedicated to St. Olaf King of Norway and St Mary Bishophill Junior which has a 10th century tower whose height was increased in the early 11th century. Medieval Following the Norman Conquest of 1066, York was substantially damaged by the punitive harrying of the north (1069) launched by William the Conqueror in response to regional revolt. Two castles were erected in the city on either side of the River Ouse. In time York became an important urban centre as the administrative centre of the county of Yorkshire, as the seat of an archbishop, and at times in the later 13th and 14th centuries as an alternative seat of royal government. It was an important trading centre. Several religious houses were founded following the Conquest, including St Mary's Abbey and Holy Trinity Priory. The city as a possession of the crown also came to house a substantial Jewish community under the protection of the sheriff. On 16 March 1190 a mob of townsfolk forced the Jews in York to flee into the castle keep (later replaced by Clifford's Tower), which was under the control of the sheriff. The castle was set on fire and the Jews were