The reign of Vytautas the Great marks both the greatest territorial expansion of the Grand Duchy and the defeat of the Teutonic Knights in the Battle of Grunwald in 1410.
It also marks the rise of the Lithuanian nobility.
After Vytautas's death, Lithuania's relationship with the Kingdom of Poland greatly deteriorates.
Lithuanian noblemen, including the Radvila family (Radziwiłłs), attempts to break the personal union with Poland.
However, the unsuccessful Muscovite–Lithuanian Wars with the Grand Duchy of Moscow forces the union to remain intact.
