Bay of Kiel
The Danish fleet subsequently blockaded the Swedish ships in the Bay of Kiel. But the Swedish fleet escaped, and the annihilation of the Danish fleet by the combined navies of Sweden and the Netherlands, after an obstinate fight between Fehmarn and Lolland at the end of September, exhausted the military resources of Denmark and compelled Christian to accept the mediation of France and the Netherlands; and peace was finally signed with the Treaty of Brömsebro on 8 February 1645. Here Denmark had to cede Gotland, Ösel and (for thirty years) Halland, while Norway lost the two provinces Jämtland and Härjedalen, giving Sweden the supremacy of the Baltic Sea.