During his reign , Lithuania reached the peak of its territorial expansion , centralization of the state began , and the Lithuanian nobility became increasingly prominent in state politics .
After two civil wars , Vytautas the Great became the Grand Duke of Lithuania in 1392 .
During Vytautas the Great 's reign , Lithuania reached the peak of Lithuania 's territorial expansion , centralization of the state began , and Lithuania Lithuanian nobility became increasingly prominent in state politics .
After two civil wars , Vytautas the Great became the Grand Duke of Lithuania in 1392 .