The Kingdom of Dyfed is one of several Welsh petty kingdoms that emerged in 5th-century post-Roman Britain in south-west Wales, based on the former Irish tribal lands of the Déisi from c 350 until it was subsumed into Deheubarth in 920. In Latin, the country of the Déisi was Demetae, eventually to evolve into Welsh as Dyfed. Following the Norman invasions of Wales between 1067–1100, the region was conquered by the Normans and by 1138 incorporated into a new shire called Pembrokeshire after the Norman castle built in the Penfro cantref, and under the rule of the Marcher Earl of Pembroke.