Europe in 1300
Wales
The British Isles in 1300
Wales was quieter, for Longshanks had subdued that nation, or was in the process of doing so (they had one more good rebellion left). As a way of tying it closer to the throne he had done two things. He was building a string of castles along the Welsh frontier and stocking them with English lords. And he had given to his eldest son the title of Prince of Wales.
It should be mentioned that the King of England also ruled in France. I'll talk more about this in a moment, but basically this was what was left from the fact that England had been conquered by French (Normans) in 1066 and had been ruled by a family (the Plantagenets) that had extensive holdings in France. Normandy had been lost by King John, but other areas remained.