Angria or Angaria is a historical region in the present-day German states of Lower Saxony and North Rhine-Westphalia. The chronicler Widukind of Corvey in his Res gestae saxonicae sive annalium libri tres denoted it as the central region of the medieval Duchy of Saxony lying along the middle reaches of the Weser river between Westphalia and Eastphalia. Its name was derived from the Germanic Angrivarii tribe which had joined the Saxon tribal confederation, and it was centered on the town of Minden, see of a bishopric since 803.