Board Thread:Spoilers!/@comment-9241531-20150811165057/@comment-24674051-20150811210034

One of the parts of the Arthurian Legend is that when Arthur ascended to power, The British were a kingdom broken, due to the attacks from the Saxons. Arthur's father, Uther Pendragon, was deposed and killed. With no ruling monarch, the British kingdom fell apart. It was Arthur, equipped with Excalibur and having formed the Knights of the Round Table, ascended and took the throne and helped to restore order to the kingdom.

So the Broken Kingdom may be a way of playing on that part of the Arthurian legend. Mind you, this is all just a wild guess.