an early Anglo-Saxon kingdom and bishopric, probably coterminous with the modern districts of East Lindsey and West Lindsey, in Lincolnshire. It was an area of early settlement by the Angles and was ruled by its own kings until the late 8th century. In the mid-7th century Northumbria had controlled Lindsey but in 678 finally lost it to the midland kingdom of Mercia. The Danes raided Lindsey in 841, wintered at Torksey in 873, and settled there soon afterward. Lindsey seems to have been recaptured by the Anglo-Saxons in 918, but place-name evidence shows Danish settlement there to have been very intense and that Lindsey supported the Danish invaders Sweyn and Canute in the early 11th century.

The Roman missionary Paulinus converted Lindsey to Christianity about 631, and it had a diocese that Theodore of Canterbury established in 679; it flourished until the time of the Danish settlement. In the mid-10th century the diocese was apparently joined to that of Dorchester on Thames (Dorchester, Oxfordshire); after the Norman Conquest (1066), the see was transferred from Dorchester to Lincoln.