Nils Carlsson Gyllenstierna af Fogelvik, a member of the Swedish baronial family of Gyllenstierna, was a Swedish field-marshal, member of the Royal Council, president of the Board of War, and governor-general of Bremen-Verden. Rewarded with the earldom of Fogelvik, he belonged to the cautious senior officers, who he hesitated when faced with Charles XII's aggressive plans, and allied with his son-in-law Arvid Horn in opposition to the King.

During the Great Northern War, the fortress of Tönning (Tønning) in the territory of Holstein-Gottorp, an ally of the Swedish Empire, was besieged twice. Denmark-Norway was forced to lift the first siege in 1700, but a combined force of the anti-Swedish coalition successfully besieged and took Tönning in 1713–1714.