Outbreak of the Great Northern War

Timeline

1. 1700Riga · LivoniaElector of Saxony and King of Poland Augustus II sent troops into Swedish Livonia and besieged Riga without taking it. King Frederick IV of Denmark attacked Sweden's ally Holstein-Gottorp. Peter I declared war on Sweden after concluding peace with the Ottomans and sent troops into Estonia. The three states hoped to dismember Sweden's Baltic empire while Charles XII was young.
2. 1700Traventhal · HolsteinWith tacit British and Dutch naval consent, Charles XII crossed the Øresund, landed at Humlebæk, and threatened Copenhagen. On 18 August Denmark signed the Treaty of Traventhal, leaving the anti-Swedish alliance and pledging not to attack Gottorp again, freeing Sweden to face the east.
3. 1700Narva · EstoniaPeter I's army besieged Narva and he himself left on the eve of the decisive battle to gather supplies. Charles XII led some 8,000–10,000 Swedish troops in a blizzard assault on a besieging Russian force four times their size; the Russian army under Croÿ collapsed and lost all its artillery. The Saxon army had already retired into winter quarters, and Sweden defeated two opponents in the war's first year, but Charles then turned his main force toward Poland, giving Russia time to recover.