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).
Electorate of Saxony
In 1756, during the Third Silesian War between Prussia and Austria (part of the Seven Years' War), Saxony was invaded and overrun by the forces of King Frederick II of Prussia, who took Dresden and after the Siege of Pirna forced the Saxon army to surrender and join his Prussian Army. Many later deserted, and a force of Saxon troops fought to restore their independence. The Treaty of Hubertusburg in 1763 eventually restored Saxony as an entity.