Emlyn

The following year, Arnulf took part in an unsuccessful rebellion (led by his elder brother) against William's successor, Henry I, in aid of Robert Curthose's claim to the throne.

[5] The king kept the lands for himself, but unlike other areas of the Lordship of Pembroke, there was never a large scale settlement of Flemings in Emlyn; it remained mostly Welsh speaking, as it continues today.

When The Anarchy broke out upon Henry's death, one of the rival claimants to the throne—Stephen—in need of allies, gave the Marcher Lordship to Gilbert de Clare (a magnate with interests nearby), and to it attached the title Earl of Pembroke.

Eventually the dispute completely fractured their authority, and Richard de Clare's son-in-law, William Marshal was able to recover the Lordship of Pembroke entirely, his power reaching Cilgerran in 1204.

[13] Early the following year, in a marriage that had probably been pre-arranged, Maredudd married Isobel, the illegitimate daughter of Gilbert's elder (but now deceased) brother, William;[12] he had effectively acquired Emlyn Uwch Cych as a dowry.

In 1282, the Statute of Rhuddlan converted the king's lands into counties, with those enfeoffed to Maredudd (including Emlyn Uwch Cych) becoming the main part of Carmarthenshire.

The part of Emlyn west of the Cuch—Emlyn Is Cych (English: Emlyn on this side of the Cuch)—remained part of the Marcher Lordship of Pembroke, which continued to be held by William Marshall's descendants until 1389, when the then Marcher Lord died without direct or male-line heirs; as a result, the territory defaulted to the crown.

Decades later, the Marcher Lordship of Pembroke was transferred to a royal favourite, who then likewise died without legitimate children, causing it to revert once more to the crown, a pattern that would repeat itself throughout the 15th century; among others it was held by Duke Humphrey (of Gloucester), William de la Pole and Jasper Tudor.