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 company with the tribe of Angles from Schleswig, a part of the Saxons settled on the island of Britain from which the Romans had withdrawn, where, as Anglo-Saxons, after having accepted Christianity about 600, they laid the foundation of Anglo-Saxon civilisation and the present Great Britain. In attempting to reach Gaul by land the Saxons came into violent conflict with the Franks living on the Rhine.