The new system was put to the test for the first time in 1700, when Sweden, under the reign of Charles XII, was attacked by a coalition of its neighbours Russia, Denmark-Norway and Saxony-Poland in the Great Northern War. The mobilization of the soldiers worked well thanks to the new system, with Sweden mobilizing 43,000 men in allotted regiments, and another 33,000 men from various enlisted regiments. The army was one of the largest in Europe at the time, having modern equipment and being very well-trained and organized. However, three enemies were too much, even though Charles XII forced Denmark to leave the war the same year it started, and forced Saxony to leave the war in 1706. After these successful blows to the coalition, Charles XII had the opportunity to sign a peace with the remaining opponent, Russia. He did not, and this decision would have immense effects on the population. Russia's vast plains did not give Charles XII the possibility to beat his enemy with his superior army; instead, he was forced into a war of attrition, a war he could not win.