Glywysing
Glywysing was, from the sub-Roman period to the Early Middle Ages, a petty kingdom in south-east Wales. Its people were descended from the Iron Age tribe of the Silures.
Name
Glywysing is said to be named after Glywys, a real or legendary early monarch, whose name may continue that of the Romano-British *Glevenses, the territory and citizens of Glevum (modern Gloucester). According to 12th-century sources, after the death of Glywys, the kingdom was divided into seven cantrefs named for his sons:Cydweli, Gwyr, Margam, Penychen, Gwynllwg, Gorfynydd, and another. These were typically ruled together by the head of the family and sometimes treated as appenage subkingdoms.
Location
The borders changed over time, but it is generally thought that its lands originally lay between the Afon Llwyd and the River Towy. At times they expanded eastwards to encompass both Gwent and Ergyng, but some time before the early 8th century, Cydweli and Gwyr (Gower) were lost to Dyfed.
Today the area of Glywysing is known as Glamorgan.