The Palatinate, historically also Rhenish Palatinate, is a region in southwestern Germany. It occupies roughly the southernmost quarter of the German federal state of Rhineland-Palatinate, covering an area of 5,451 square kilometers. Its residents are known as Palatines. Formerly a Celtic region, this area was conquered by the Roman Empire under Emperor Augustus in about 12 BCE, whereafter it was part of the Germania Superior province. During the decay of the Empire, Alamanni tribes settled here.