Gustav Vasa was born on 12 May 1496 to Erik Johansson Vasa and Cecilia Mansdotter. In 1521 he was appointed regent against the king Christian II of Denmark, who took over Sweden and centerlized his realm around Denmark. People were angry and Christian was overthrown. In 1523 this unknown figure became a ruler of a centerless realm, he took up Lutheranism and created a strong centralized government. He became known as the father of Sweden and started the House of Vasa as the first purely Swedish kings. In 1531 he married Clara of Saxe-Lauenburg, daughter of another Lutheran, Magnus I, Duke of Saxe-Lauenburg. They soon had a son (1532) who was named after Erik J. Vasa who died two years after Gustav's birth and he later became Eric XIV. In 1534 the second heir to the throne was born, another son John and their final child was a daughter (1537) Cecilia. In 1523 he wanted to sign a peace treary with Christian's succesor and overthrower (his uncle) Frederick I. Whoever this try fell throw and he had to wait until 1535, when Frederick's succesor Christian III, who was Lutheran, came to the throne, this time the alliance was made and Christian proclaimed: The Kalmar Union is not yet dead. His protestant beliefs didn't go well with both Pius IV and Alexander VII and he was almost excommunicated. In 1539 when Gregory XIII proclaimed he would try to talk with the Lutherans he wanted Gustav to relate his message to Clement VII. This, however, failed and before the talks got anywhere Gregory died. Afterward he tried to pay all cardinals to put non-fanatical Popes on the Holy See. He put both Innocent IX and Alexander VIII into the Vatican. In 1553, angry Alexander VIII, for whom Sixtus VI's demands were over the top declared a Crusade. Gustav I quickly swore to be Catholic again, though secretly still being Lutheran. In 1557, his health went down and on 22 February 1558 he told his son Eric and other nobles to stay united and keep Sweden strong.