In the Concert of The Hague, the Dutch Republic, the Commonwealth of England and the Kingdom of France set out their views on how the Second Northern War should end.

The Concert of The Hague, signed on 21 May 1659, was an outline of the common stance of England, France and the Dutch Republic regarding the Second Northern War. The powers agreed that the Swedish Empire and Denmark–Norway should settle for a peace treaty based on the Treaty of Roskilde, including free navigation through The Sound and the Baltic Sea based on the Treaty of Elbing. The subsequent Dano-Swedish Peace of Copenhagen largely followed the terms dictated by the Concert of the Hague.

The Republic of the Seven United Netherlands (Dutch: Republiek der Zeven Verenigde Nederlanden), also known as the United Provinces (of the Netherlands), and referred to in historiography as the Dutch Republic, was a confederation that existed from 1588 until the Batavian Revolution in 1795. It was a predecessor state of the present-day Netherlands and the first independent Dutch nation state. The republic was established after seven Dutch provinces in the Spanish Netherlands revolted against Spanish rule, forming a mutual alliance against Spain in 1579 (the Union of Utrecht) and declaring their independence in 1581 (the Act of Abjuration), after which they confederated in 1588 (the Instruction of 12 April 1588) after the States General could not agree on a new monarch. The seven provinces it comprised were Groningen (present-day Groningen), Frisia (present-day Friesland), Overijssel (present-day Overijssel), Guelders (present-day Gelderland), Utrecht (present-day Utrecht), Holland (present-day North Holland and South Holland), and Zeeland (present-day Zeeland).

The Commonwealth of England was the political structure during the period from 1649 to 1660 when the Kingdom of England, later along with Ireland and Scotland, were governed as a republic after the end of the Second English Civil War and the trial and execution of Charles I. The republic's existence was declared through "An Act declaring England to be a Commonwealth", adopted by the Rump Parliament on 19 May 1649. Power in the early Commonwealth was vested primarily in the Parliament and a Council of State. During the period, fighting continued, particularly in Ireland and Scotland, between the parliamentary forces and those opposed to them, in the Cromwellian conquest of Ireland and the Anglo-Scottish war of 1650–1652.