Treaty of Leipzig in the context of Ernest, Elector of Saxony

The House of Wettin (German: Haus Wettin) is a dynasty which included Saxon kings, prince-electors, dukes, and counts, who once ruled territories in the present-day German federated states of Saxony, Saxony-Anhalt and Thuringia. The dynasty is one of the oldest in Europe, and its origins can be traced back to the town of Wettin, Saxony-Anhalt. The Wettins gradually rose to power within the Holy Roman Empire. Members of the family became the rulers of several medieval states, starting with the Saxon Eastern March in 1030. Other states they gained were Meissen in 1089, Thuringia in 1263, and Saxony in 1423. These areas cover large parts of Central Germany as a cultural area of Germany.

The family divided into two ruling branches in 1485 by the Treaty of Leipzig: the Ernestine and Albertine branches. The older Ernestine branch played a key role during the Protestant Reformation. Many ruling monarchs outside Germany were later tied to its cadet branch, the House of Saxe-Coburg and Gotha. The Albertine branch, while less prominent, ruled most of Saxony and played a part in Polish history.

Frederick II, The Gentle (German: Friedrich, der Sanftmütige'; Frederick the Gentle; 22 August 1412 – 7 September 1464) was Elector of Saxony (1428–1464) and Landgrave of Thuringia (1440–1445). His succession laid the basis for the later division of the House of Wettin, as his two sons, Ernest and Albert, inherited his territories jointly before eventually forming the Ernestine and Albertine branches through the Treaty of Leipzig (1485).