The Land of the Five Boroughs

 The Five Boroughs, separate Danish jarldoms, were centred on Lincoln, Leicester, Derby, Nottingham and Stamford, all in former east Mercia. They take their name from an Old English poem preserved in the Anglo-Saxon Chronicle under the year 942, which describes their ultimate conquest by King Edmund of Wessex. It is not known whether the label of the 'Five Boroughs' was used before this date, but it is a highly convenient one for my purposes.