A major reason why Sweden could be so successful in wars with such a scarce number of soldiers was its advanced military tactics. Sweden was able to reform its military tactics continuously throughout the period. Prior to Gustavus Adolphus's reforms, both his father, Charles IX, and his uncle Erik XIV had tried to reform the army but had effectively failed to do so. Charles IX, like most other rulers, had tried to implement the Dutch system into the army but with limited success. The lack of a strict organisation in the infantry caused the proportion of pikemen to musketeers to be far lower than the preferred ratio of 1 to 1. This, combined with the lack of funds to provide the soldiers with armour, caused the Swedish infantry to be dangerously lightly equipped and unable to deal with cavalry or heavier infantry in open terrain. Charles IX was, however, able to implement the Dutch system for fighting in caracole among the cavalry, with unfortunate results. His partially reformed army suffered a disastrous defeat at Kircholm against a Polish-Lithuanian army led by Jan Karol Chodkiewicz. The Hussaria were the last shock cavalry in Europe still fighting with lances, yet they proved with terrifying effect the superiority of aggressive charging compared to the more defensive caracole used in the rest of Europe. In the end, Charles IX's revolt against his nephew Sigismund of Poland and subsequent rise to the throne of Sweden caused a dynastic struggle for the throne of Sweden that would not finally end until the treaty of Oliva in 1660.