Polish–Lithuanian Wars (13th–14th centuries)
During the Polish–Lithuanian wars of the 13th and 14th centuries, the neighbouring Lithuanian state (Kingdom and Grand Duchy at different times) and Polish states, especially Duchy of Masovia, frequently clashed.
Sometimes, the armed clashes took the form of plundering expeditions organized by Lithuanian princes (Kunigas) on Polish lands. The aim of these expeditions was not to seize territory, but to seize prisoners and loot. These expeditions sometimes caused retaliatory actions by Polish princes on the territory of Lithuania. These fights, although interrupted by a temporary alliance between Władysław I Łokietek and Gediminas, lasted in practice until the Act of Krėva in 1385