How did Algirdas extend Lithuania’s territory toward the Black Sea?

Grand Duke Algirdas extended Lithuania’s territory toward the Black Sea primarily by capitalizing on the decline of the Golden Horde after 1357.1

His expansionist efforts involved several key military actions:

• Campaigns against the Tatars: In 1362–1363, Algirdas campaigned in Tatar-controlled territories, achieving a decisive victory against three Tatar governors at the Battle of the River Siniye Vody.1
• Securing Strategic Regions: Through these military successes, he secured the principality of Kiev, which he placed under the rule of his son Vladimir, and liberated Little Podolia from the authority of the Golden Horde.1

By conquering these vast East Slavic and Tatar territories, Algirdas successfully stretched the domain of the Grand Duchy of Lithuania from the Baltic to the Black Sea, establishing it as one of the most influential powers in eastern Europe.12