| Treaty of Nyborg | |
| Context: | Succession to the Duchy of Schleswig |
| Date Signed: | 15 August 1384 |
| Location Signed: | Nyborg |
| Negotiators: | Margaret I King Oluf Nicholas I Gerhard VI |
| Parties: | Holstein-Rendsburg |
The Treaty of Nyborg, also known as the Meeting at Nyborg, was a peace treaty between Queen Margaret I of Denmark and the German dukes, Henry II and Nicholas I, Count of Holstein-Rendsburg on a territorial and successional dispute in Schleswig. The treaty was signed during a meeting in Nyborg on Funen on 15 August 1386 and stated that the Holsteinians were to hold the Duchy of Schleswig for eternity.[1]
In 1375, Schleswig was roughly split between Henry, Duke of Schleswig in the North, and the Counts of Holstein-Rendsburg, Henry II and Nicholas I in the South. However, after the death of Duke Henry of Schleswig the same year, the northern part of Schleswig laid open to Holsteinian invasion. Queen Margaret, who was the de facto leader of Denmark and Norway, was unable to secure Denmark's southern border since she had all her resources and attention elsewhere. Subsequently, the two dukes invaded Northern Schleswig, quickly taking the island of Als and the two towns of Haderslev and Tønder. The occupation would only be officially confirmed by Denmark years later in 1386, when the two parties would meet at Nyborg.
At Nyborg, King Oluf and Margaret would grant the Duchy of Schleswig to the sons of Henry II of Holstein-Rendsburg, who had died earlier in the year, and Oluf and Margaret would concurrently reconcile with Count Nicholas I. The German, Presbyter Bremensis, would give a detailed description of the stipulations in his Chronicon Holtzatiae:
Margaret would, however, invade Schleswig in 1404 after the death of Count Gerhard VI. Here, Margaret would spend much of the rest of her life combatting the Holsteinians, and it would also be here, specifically in Flensburg, where she would die presumeable from the Bubonic plague.[2]