The history of Wales as an independent nation ended quite early when it was annexed by England in 1284, as in OTL.
In Wales, the English encountered a new weapon, the Welsh longbows, which they used to their advantage in their wars against Scotland and France, winning several battles in the First Aquitainian War.
During the years 1633-50, Welsh uprisings happened during the War of the 'fords. Some were expelled to Atlantis, where they settled around Boston.
After the War of the 'fords, Wales became an integral part of England in 1655. The Welsh language was suppressed. (This happened about one century later than OTL, since the English kings were preoccupied with the rest of their empire. Now, under the Staffords, they cared more about the islands.)
1846, the Socialists overwhelmed last resistors in Scotland, Wales and Ireland, adding them to their sphere of influence.