Kingdom of Lindsey
Haethfieldlande or Hatfield was another minor Anglo-Saxon kingdom listed in the Tribal Hidage. Very little is known about Hatfield and nothing of its kings. Unlike other petty kingdoms in this area of Britain, the name here is of Anglo-Saxon origin and not British. According to the Tribal Hidage, 'Hatfield-land' was merged with Lindsey into a single kingdom. Afterwards it became known simply as Hatfield Chase, an area on the west part of Lindsey, later part of Yorkshire and Lincolnshire. Hatfield was the site of a synod held by Theodore, the Archbishop of Canterbury . It was a royal residence of several kings of Northumbria. Edwin of Northumbria was killed here at the Battle of Hatfield Chase on 12 October 633. Later, Hatfield became a part of the East Riding of Yorkshire.