The following will contain a history of the Reach starting with Aegon's Conquest.
Lord Edmund "the King who Knelt" Gardener
Edmund Gardener was the last Gardener King of the Reach. He was not given the privilege of serving as a Lord Paramount by Aegon "the Kinglsayer King" Targaryen. Aegon Targaryen instead split the Reach into two seperate entities, the Southern Reach (known colloquially as the Crownlands) consisting of The Arbor, Oldtown, the Westmarch, Brightwater and the Shields. The remained of the Reach was renamed into the Nothern Reach.