Through the will of her father received an inheritance, the duchy of S dermanland, which included the province of the same name and some parts of N rke and V stmanland. His dignity of duke allow him to rule the region almost as sovereign. However, it could assert their rights during the reign of his brother Erik XIV. As a teenager, Charles received military training, and stress in the artillery branch. Precisely because of his military prowess in 1568 successfully participate in the uprising against Erik XIV, led by his brother John. Erik’s overthrow in 1569, John would get the crown, and Charles could take possession of his dukedom and acquire a position of great influence in the country. When King John III went over to Catholicism, Carlos was the strongest opponents.The king had been educated to the Crown Prince Sigismund, in the Catholic religion, in order to make it a candidate for the Polish throne and achieve a union between Sweden and Poland. Charles ran for maintaining the independence of Sweden initiated by Gustav Vasa and maintain Lutheranism as the state religion. On the death of John III in 1592, it became clear the influence of , then he and the council headed the provisional government that ruled in the moments before the arrival of the heir, King Sigismund III of Poland. The religious question, as in the days of the former king would be taken up again, this time with greater interest, as Sigismund was a devout Catholic and supporter of the Counter feared the possibility that it sought to return to Sweden to papal authority. Sigismund, on his arrival, he promised before the council of religious freedom in Sweden, and under this promise was crowned in Uppsala in 1594. But the new king had commitments in Poland and his stay in Sweden would be very short.Decided to leave a government on their behalf in the summer of 1594. Duke Charles and the advice offered proposals to maintain the country’s independence in the new personal union with Poland. Perhaps because of its defense of Lutheranism, Carlos found the support of the board and part of the aristocracy, though the duke wanted to take over some sort of internship during the king’s absence. The king granted administrative functions as both the council to Charles, but his powers remained ambiguous, and instead preferred to give counts of lieutenants to several of his colleagues, who favored the Catholic interests. In this situation rebelled Duke Charles, and in partnership with the council, proclaimed himself “Supreme Head and regent of the kingdom” and began to govern on its own. Charles summoned a parliament in 1595 in S derk ping, there was full power to exercise the regency.