Llywelyn was careful not to provoke unnecessary hostilities with the crown or the Marcher lords; for example, in 1220, he compelled Rhys Gryg to return four commotes in South Wales to their previous Anglo-Norman owners. He built a number of castles to defend his borders, most thought to have been built between 1220 and 1230. These were the first sophisticated stone castles in Wales; his castles at Criccieth, Deganwy, Dolbadarn, Dolwyddelan and Castell y Bere are among the best examples. Llywelyn also appears to have fostered the development of quasi-urban settlements in Gwynedd to act as centres of trade.
llywelyn was careful not to provoke unnecessary hostilities with the crown or the marcher lords; for example in 1220 he compelled rhys gryg to return four commotes in south wales to their previous anglo-norman owners he built a number of castles to defend his borders most thought to have been built between 1220 and 1230 these were the first sophisticated stone castles in wales; his castles at criccieth deganwy dolbadarn dolwyddelan and castell y bere are among the best examples llywelyn also appears to have fostered the development of quasi-urban settlements in gwynedd to act as centres of trade