Westphalia (tribal duchy of Saxony)
Map of the tribal duchy of Saxony and the property ( house power ) of Heinrich the Lion shortly before it was broken up around 1180; Westphalia is a property located to the west
In the Middle Ages, Westphalia was the western part of the Duchy of Saxony . It encompassed today's Westphalia (excluding East Westphalia ) and the west of Lower Saxony , which adjoins it to the north, until just before the North Sea and almost all of the catchment areas of the Ruhr , Lippe and Ems . In the (north) east it was separated from the Engern to the east by the Hunte and the estuary of the Weser .