While the historic region of Swabia takes its name from the ancient Suebi, dwelling in the angle formed by the Rhine and the Danube, the stem duchy comprised a much larger territory, stretching from the Alsatian Vosges mountain range in the west to the right bank of the river Lech in the east and up to Chiavenna (Kleven) and Gotthard Pass in the south. The name of the larger stem duchy was often used interchangeably with Alamannia during the High Middle Ages, until about the 11th century, when the form Swabia began to prevail.