Upper Saxony
It was particularly to distinguish the lands from 'Lower Saxony', a concept which arose later in popular usage (though never enforced) as a term for the original Saxon lands in north and west Germany (where Low German dialects had spread), in what is now the state of Lower Saxony, as well as the adjacent Westphalian region, Holstein and the western part of today's Saxony-Anhalt north of the Harz range (Eastphalia).
History of Saxony
In 3rd and 4th century Germany, great tribal confederations of the Alamanni, Bavarians, Thuringians, Franks, Frisii, and Saxons arose. These took the place of the numerous petty tribes with their popular tribal form of government. With the exceptions of the Saxons, all these confederations were ruled by kings; the Saxons were divided into a number of independent bodies under different chiefs, and in time of war these chieftains drew lots. The selected leader was followed by the other chiefs until the war ended.