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).
Kingdom of Saxony
Following the defeat of Saxony's ally Prussia at the Battle of Jena in 1806, Saxony joined the Confederation of the Rhine, and remained within the Confederation until its dissolution in 1813 with Napoleon's defeat at the Battle of Leipzig. Following the battle, in which Saxony — virtually alone of all the German states — had fought alongside the French. King Frederick Augustus I was deserted by his troops, taken prisoner by the Prussians and considered to have forfeited his throne by the allies, who put Saxony under Prussian occupation and administration. This was probably more due to the Prussian desire to annex Saxony than to any crime on Frederick Augustus's part, and the fate of Saxony would prove to be one of the main issues at the Congress of Vienna. In the end, 40% of the Kingdom, including the historically significant Wittenberg, home of the Protestant Reformation, was annexed by Prussia, but Frederick Augustus was restored to the throne in the remainder of his kingdom, which still included the major cities of Dresden and Leipzig. The Kingdom also joined the German Confederation, the new organization of the German states to replace the fallen Holy Roman Empire.