Saxon
The Saxons are the people of Thuringia and Upper Saxony, heirs to the Old Saxons of northern Germany and the medieval eastward colonization. The Old Saxons held the lands between the Ems and the Elbe until Charlemagne subdued them in the long Saxon Wars of 772 to 804, forced their conversion and made their country a Frankish stem duchy.
From about 1100 the Ostsiedlung carried settlers from Saxony, Franconia and Thuringia into the Margraviate of Meissen between the Elbe and Saale, formerly Polabian Slav country; their mixed speech hardened into the Upper Saxon koiné, linked to Thuringian dialects.
In the later Middle Ages Meissen chancery Saxon became the administrative language of the Electorate of Saxony after 1423, and Martin Luther's Bible translation of the 1520s and 1530s in this Central German idiom made it a chief foundation of standard German. Saxon speech carried Leipzig elite prestige until the Electorate's decline after the Seven Years' War of 1756 to 1763.