Morgannwg

Morgannwg was a kingdom in south-east Wales, the name used for Glywysing from the late tenth century. Its last native ruler, Iestyn ap Gwrgant, probably based himself at Dinas Powys near Cardiff; Robert Fitzhamon overthrew him around 1091. The kingdom became the marcher lordship of Glamorgan, and in 1536 Glamorgan became a Welsh county under English rule.