The latter was an ally of Prussia as a member of the Fourth Coalition against France.
It was defeated in the battles of Jena and Auerstedt and partially occupied by French troops.
[1] The peace treaty was negotiated, for the French, by Charles Maurice de Talleyrand.
[2] According to its terms, the electorate became the Kingdom of Saxony and annexed certain territories (including Cottbus) taken from Prussia.
[2][3] Saxony had to ceded a small amount of territory in its west to the new Kingdom of Westphalia.