| Frederick II | |
| Succession: | Elector of Saxony |
| Reign: | 4 January 1428 - 7 September 1464 |
| Predecessor: | Frederick I |
| Successor: | Ernest |
| Succession1: | Landgrave of Thuringia |
| Reign1: | 7 May 1440 - 1445 |
| Predecessor1: | Frederick IV |
| Successor1: | William II |
| Succession2: | Margrave of Meissen and Duke of Saxony |
| Reign2: | 4 January 1428 - 7 September 1464 |
| Predecessor2: | Frederick IV/I |
| Successor2: | Albert IV/III |
| Issue: | Amalia, Duchess of Bavaria Anna, Electress of Brandenburg Ernest, Elector of Saxony Albert, Duke of Saxony Hedwig, Abbess of Quedlinburg |
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| Issue-Pipe: | among others... |
| House: | House of Wettin |
| Father: | Frederick I, Elector of Saxony |
| Mother: | Catherine of Brunswick and Lunenburg |
| Birth Date: | 22 August 1412 |
| Birth Place: | Leipzig, Electorate of Saxony, Holy Roman Empire |
| Death Place: | Leipzig, Electorate of Saxony, Holy Roman Empire |
| Burial Place: | Meissen Cathedral |
Frederick II, The Gentle (Friedrich, der Sanftmütige; Frederick the Gentle; 22 August 1412 – 7 September 1464) was Elector of Saxony (1428–1464) and was Landgrave of Thuringia (1440–1445).
Frederick was born in Leipzig, the eldest of the seven children of Frederick I, Elector of Saxony, and Catherine of Brunswick and Lunenburg.
After the death of his father in 1428 he took over the government together with his younger brothers William III, Henry and Sigismund. In 1433 the Wettins finally concluded peace with the Hussites and in 1438 Frederick led Saxon forces to victory in the Battle of Sellnitz. That same year it was considered the first federal state parliament of Saxony. The parliament received the right to find together in case of innovations in fiscal matters also without summoning by the ruler.
Also in 1438 it was decided that Frederick, and not his rival Bernard IV, duke of Saxe-Lauenburg, was entitled to exercise the Saxon electoral vote at the elections for the German throne. The elector then aided Albert II to secure this dignity, performing a similar service for his own brother-in-law, Frederick two years later.
After Henry's death in 1435, and Sigismund was forced to renounce and became a bishop (in 1440), Frederick and William divided their possessions. In the Division of Altenburg in 1445, William III received the Thuringian and Frankish part, and Frederick got the Eastern part of the principality. The mines remained common possessions. Disputes over the distribution led however in 1446 to the Saxon Brother War, which found an end only on 27 January 1451 with the peace of Naumburg. In the Treaty of Eger in (1459), elector Frederick, Duke William III and the king of Bohemia George of Podebrady fixed the borders between Bohemia and Saxony, at the height of the Ore Mountains (German: Erzgebirge) and the middle of the Elbe which still holds today. It belongs therefore to the oldest still existing borders of Europe.
After the death of Frederick, in Leipzig, both of his sons, Ernest and Albert, first took over the government together. After Duke William III died in 1482, Thuringia returned to Frederick's line.
In Leipzig, Electoral Saxony on 3 June 1431 Frederick married Margaret of Austria, the daughter of Ernest of Austria and Cymburgis of Masovia. They had eight children:
July 1455 saw the Prinzenraub, the attempt of a knight named Kunz von Kaufungen to abduct Frederick's sons Ernest and Albert. Having carried them off from Altenburg, Kunz was making his way to Bohemia when the plot was accidentally discovered and the princes restored.