Polish–Lithuanian Commonwealth Navy was the navy of the Polish–Lithuanian Commonwealth.
The Commonwealth Navy was small and played a relatively minor role in the history of the Commonwealth. Despite having access to the Baltic Sea, neither Poland nor Lithuania had any significant navy throughout their histories.
At the turn of the seventeenth century, Poland became ruled by the House of Vasa, and was involved in a series of wars with Sweden (see also dominium maris baltici). Vasa kings attempted to create a proper fleet, but their attempts met with repeated failures, due to lack of funds in the royal treasury (Polish nobility saw little need for the fleet and refused to raise taxes for its construction, and Gdańsk continued its opposition to the idea of a royal fleet). During the reign of Sigismund III, the most celebrated victory of the Commonwealth Navy under command of Admiral Arend Dickmann took place at the Battle of Oliwa in 1627 against Sweden, during the Polish-Swedish War. The victory over Sweden secured for Poland permanent access to the Atlantic, and laid the foundations for expeditions beyond Europe. The plans for the independent fleet fell through shortly afterwards due to a badly executed alliance with the Habsburgs who in 1629 took over the fleet.
The Commission of Royal Ships (Komisja Okrętów Królewskich) was created in 1625. This commission, along with the ultimate allocation of funds by the Sejm in 1637, attempted to create a permanent Commonwealth Navy. Władysław IV Waza who took the throne in 1632 bought 12 ships, and built a dedicated port for the royal navy (Władysławowo).