The Bison Trap: Jogaila 1994 on netflix

Grand Duke Algerd sees his beloved son Jogaila as his successor. His brother, Samogitian Prince Kęstutis, also has six sons, including his beloved Vytautas, but he swears an oath to his brother that Jogaila will become the Grand Duke. And so it happened. Jogaila inherited a powerful state that stretched from the Baltic to the Black Sea. However, his own eleven brothers and six sons of Kęstutis do not promise a peaceful life. Jogaila decides to strike first.