648 Outlines of European History Gustavus Adolphus victorious at Breitenfeld, 1631 We have had no occasion hitherto to speak of the Scandinavian kingdoms of Norway, Sweden, and Denmark, which the northern German peoples had established about Charlemagne's time ; but from now on they begin to take part in the affairs of central Europe. The Union of Calmar (1397) had brought these three kingdoms, previously separate, under a single ruler. About the time that the Protestant revolt began in Germany the union was broken by the withdrawal of Sweden, which became an independ- ent kingdom. Gustavus Vasa, a Swedish noble, led the move- ment and was subsequently chosen king of Sweden (1523). In the same year Protestantism was introduced. Vasa confiscated the church lands, got the better of the aristocracy, — who had formerly made the kings a great deal of trouble, — and started Sweden on its way toward national greatness. Gustavus Adolphus (i 594-1 632) was induced to invade Germany for two reasons. In the first place, he was a sincere and enthusiastic Protestant and by far the most generous and attractive figure of his time. He was genuinely afflicted by the misfortunes of his Protestant brethren and anxious to devote himself to their welfare. Secondly, he undoubtedly hoped by his invasion not only to free his fellow Protestants from the oppression of the Emperor and of the Catholic League, but to gain a strip of German territory for Sweden. Gustavus was not received with much cordiality at first by the Protestant princes of the north, but they were brought to their senses by the awful destruction of Magdeburg by the troops of the Catholic League under General Tilly. Magdeburg was the most important town of northern Germany. When it finally succumbed after an obstinate and difficult siege, twenty thousand of its inhabitants were killed and the town burned to the ground. Although Tilly's reputation for cruelty is quite equal to that of Wallenstein, he was probably not responsible for the fire. After Gustavus Adolphus had met Tilly near Leipsic and victoriously routed the army of the League, the Protestant princes began to look with more favor on the foreigner.
