At Bornholm, on May 30, 1563, the Danish fleet fired on the Swedish navy. A battle arose that ended with Danish defeat. German royal emissaries were sent to negotiate a peace, but at the meeting place of Rostock no Swedes appeared. On August 13, 1563, war was declared in Stockholm by emissaries from Denmark and Lübeck. The so-called Northern Seven Years' War commenced, with exhausting assault on land and water. Eric undaunted continued the war until his insanity in 1567 halted the Swedish warfare. He was dethroned in 1568 and replaced by John, who made peace attempts, which were eventually successful by the Treaty of Stettin in 1570.