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).
List of rulers of Saxony
The Ascanian line of Saxe-Wittenberg became extinct with the death of Elector Albert III in 1422, whereafter Emperor Sigismund bestowed the country and electoral dignity upon Margrave Frederick IV of Meissen, who had been a loyal supporter in the Hussite Wars. Late Albert's Ascanian relative Duke Eric V of Saxe-Lauenburg protested in vain. Frederick, now one of the seven Prince-electors, was a member of the House of Wettin, which since 1089 had ruled over the adjacent Margraviate of Meissen up the Elbe river, established under Emperor Otto I in 965, and since 1242 also over the Landgraviate of Thuringia. Thus, in 1423, Saxe-Wittenberg, the Margraviate of Meissen and Thuringia were united under one ruler, and the unified territory .
gradually received the name of (Upper) Saxony (or simply Saxony).