The Swedish Deluge refers to a series of conflicts in the mid-17th century, primarily between the Kingdom of Sweden and the Polish-Lithuanian Commonwealth. This period, lasting from 1655 to 1660, was marked by military invasions, territorial disputes, and significant destruction in the region. The war was part of a larger struggle for power in Northern Europe. The conflict began when Swedish forces invaded Poland, taking advantage of internal strife within the Commonwealth. The war saw notable battles and shifting alliances, ultimately leading to the Treaty of Oliva in 1660, which established peace and defined territorial boundaries, significantly impacting the balance of power in Europe.