The Thirty Years' War, fought in 1618-1648, was one of the most important conflicts of the 17th century, which had a huge impact on the relationship of power between the then powers. In some simplification, it can be assumed that the peace ending it, i.e. the Peace of Westphalia of 1648, made France (along with the Pyrenean Peace of 1659) a leading power in the Old Continent, and significantly weakened the position of the Habsburgs in Europe. It is also worth remembering that the great winner of the Thirty Years War was also Sweden, which owed its superpower position primarily to its great army. Its profound reforms were carried out by Gustav II Adolf of the Vasa dynasty, ruling in the years 1611-1632. This outstanding ruler made significant changes to the infantry. First of all, the Swedish native population was conscripted into infantry on a larger scale. Companies (with a force of 150 people) and squadrons with a force of 600 were also introduced as tactical units. On the other hand, two squadrons formed an infantry regiment. This infantry was composed of musketeers and pikemen - which was, by the way, a standard in Western Europe at that time. However, Gustav II Adolf increased the role of pikemen on the battlefield, who from a purely defensive formation began to become an offensive formation. Musketeers also received gunpowder loads in paper "patrons", which accelerated the process of loading the muskets. The command of the Swedish infantry was also improved by creating "staffs" in each regiment and company. The quality of the Swedish infantry can be proved not only by the battles of the Swedish-Polish war of 1626-1629, but also by the battles at Breitenfeld (1631) or at Lützen (1632), which, however, ended with the death of Gustav II Adolf, who during his lifetime received the nickname Lion North.