CEDEWAIN Or, Cydewain.
Commote in eastern Wales, west of Montgomery, in the upper Severn valley. It lay on the southern fringes of Powys, which tried to dominate it, but it also attracted the attention of the powerful Kingdom of Deheubarth in the 11th century and of Gwynedd in the 13th. It is possible that Cedewain was originally a cantref that included Ceri, which lay to the south of it.
In 1273 Llywelyn ap Gruffydd of Gwynedd began to construct a castle at Dolforwyn, which would have secured his domination of Cedewain. It would also threaten both the Prince of South Powys in his home at Welshpool and the royal castle at Montgomery. The result was the war of 1276-7, which curtailed the power of Gwynedd.
Afterwards the King of England gave Cedewain to the powerful Marcher family of Mortimer in 1279. From them it passed by inheritance to the Duke of York in 1425 and thus in 1461 to the Crown. It became part of Montgomeryshire in 1536.