Why is "Earl of Northumbria" trending?

Wikipedia Overview

Earl of Northumbria or Ealdorman of Northumbria was a title in the late Anglo-Saxon, Anglo-Scandinavian and early Anglo-Norman period in England. The ealdordom was a successor of the Norse Kingdom of York. In the seventh century, the Anglo-Saxon kingdoms of Bernicia and Deira were united in the kingdom of Northumbria, but this was destroyed by the Vikings in 867. Southern Northumbria, the former Deira, then became the Viking kingdom of York, while the rulers of Bamburgh commanded territory roughly equivalent to the northern kingdom of Bernicia. In 1006 Uhtred the Bold, ruler of Bamburgh, by command of Æthelred the Unready became ealdorman in the south, temporarily re-uniting much of the area of Northumbria into a single jurisdiction. Uhtred was murdered in 1016, and Cnut then appointed Eric of Hlathir ealdorman at York, but Uhtred's dynasty held onto Bamburgh. After the Norman Conquest the region was divided into multiple smaller baronies, one of which was the earldom of Northumberland, with others like the earldoms of York and numerous autonomous liberties such as the County Palatine of Durham and Liberty of Tynedale.