1700: Denmark, Riga and Narva
Frederik IV of Denmark–Norway directed his first attack against Sweden's ally Holstein-Gottorp. In 1697, Danish forces had leveled several of Gottorp's fortresses. In March 1700, a Danish army laid siege to Tönning. Simultaneously, Augustus II's forces advanced through Swedish Livonia, captured Dünamünde and laid siege to Riga. Earlier attempts to storm Riga had been made in December 1699.
Charles XII of Sweden first focused on attacking Denmark. The Swedish navy was able to outmaneuver the Danish Sound blockade and deploy an army near the Danish capital, Copenhagen. This surprise move and pressure by the Maritime Powers (Great Britain and the Dutch Republic) forced Denmark–Norway to withdraw from the war in August 1700 according to the terms of the Peace of Travendal.
Charles XII was now able to speedily deploy his army to the eastern coast of the Baltic Sea and face his remaining enemies: besides the army of Augustus II in Livonia, an army of Russian tsar Peter I was already on its way to invade Swedish Ingria, where it laid siege to Narva in October. In November, the Russian and Swedish armies met at the First Battle of Narva where the Russians suffered a crushing defeat.
After the dissolution of the first coalition through the peace of Travendal and with the victory at Narva; the Swedish chancellor, Benedict Oxenstjerna, attempted to use the bidding for the favor of Sweden by France and the Maritime Powers (then on the eve of the War of the Spanish Succession) to end the war and make Charles an arbiter of Europe.
Read more about this topic: Great Northern War