North of the Ottoman Empire, several Christian dynasties also built up their power and worked toward creating stronger states. Like Aragon and Castile, the crowns of Poland and Lithuania were joined together by a marriage, though this one also involved a conversion – in 1386, Queen Jadwiga of Poland married Jagaila (Jagiello in Polish), the pagan grand duke of Lithuania, who was baptized with the Christian name of Wladyslaw and promised to convert his subjects to Christianity. Each country remained largely self-governing, and under the Jagiellonian dynasty Poland-Lithuania expanded its territory to cover a large part of central and eastern Europe, including what is now Belarus and Ukraine. In 1493, the fi rst national parliament (the Sejm , pronounced like “same” in English) was established in Poland, and in 1569 Poland and Lithuania were united under a single parliament. Nobles dominated this parliament, however, and when the last Jagiellonian monarch died in 1572, they asserted their right to be consulted on foreign policy matters and to elect the kings. They often chose foreigners without local bases of power rather than elevating a native noble family to the monarchy. Poland-Lithuania defeated the Teutonic Knights and their allies the Livonian Brethren of the Sword, military religious orders who together controlled much of the Baltic region, several times during the fi fteenth century. This halted the advance of Germans eastward, which had begun in the fourteenth century under the protection of the Teutonic Knights. In 1525, the Teutonic Knights themselves underwent a conversion, when their last Grand Master, Albert of Brandenburg, a member of the Hohenzollern family, became a Lutheran. Albert changed their territory from a religious state to the secular duchy of Prussia, under the overlordship of the king of Poland-Lithuania. To the east of Poland-Lithuania, the decline in the power of the Mongols in the late fourteenth century allowed the grand dukes of Muscovy to expand their holdings. During the fi fteenth century, the grand dukes Basil I (ruled 1389–1425) and Basil II (ruled 1425–62) fi rmed up their alliance with the eastern Christian church and rewarded high-ranking landowners (boyars) with positions as army offi cers and government offi cials. Ivan III (ruled 1462–1505) married the niece of the last Byzantine emperor, thus both symbolically and genealogically tying himself to the legacy of Rome. Church and court offi cials began to talk of Moscow as the “third Rome,” and Ivan’s grandson Ivan IV (called “the Terrible,” ruled 1533–84) gave himself the title of caesar (“tsar” in Russian) in 1547 to further reinforce this link. Ivan IV was even more effective than French or Spanish monarchs at curbing the independent power of the great nobles. Using a special police force, he ordered the arrest and murder of hundreds of aristocrats and gave his victims’ estates as payment to those landowners – usually members of the lesser nobility – serving in his army or government, often referred to as the “service nobility” and thus similar to the French noblesse de robe . Ivan III and Ivan IV expanded Muscovite territory both westward and eastward, annexing several cities, including Novgorod, whose inhabitants were massacred. They attacked Livonia, and seized Tatar states east of the Ural Mountains in order to control access to the Caspian Sea. The leader of the Russian Orthodox Church, the patriarch, came under the direct control of the tsar. Northern Europe also saw a series of confl icts between rulers and the nobility in the thirteenth and fourteenth centuries, set against a backdrop of moves by German cities who had joined together to form the Hanseatic League to gain monopoly control of the fur and fi sh trade. In 1388, Swedish nobles turned to Queen Margrete of Denmark, the widow of King Haakon VI of Norway, for help in opposing the Germans. Their combined efforts were successful, and in 1397 a treaty set up the Union of Kalmar uniting Denmark, Norway, and Sweden under Margrete. The treaty provided for a common foreign policy, but separate national councils and the continuation of existing laws in each country. Both Denmark–Norway and Sweden (which included what is now Finland) developed representative assemblies ( Riksdag ), with lawmaking and taxation powers. The Swedish Riksdag was unique, because along with the usual estates of clergy, nobility, and bourgeois, it had a fourth estate for peasants. During the early sixteenth century, Swedish nobles became increasingly dissatisfi ed with the Union of Kalmar, and after several years of war, in 1523 the Swedes defeated the Danes and established their own monarchy under Gustav Vasa, a member of a prominent Swedish noble family. Like his contemporaries Francis I of France and Henry VIII of England, Gustavus Vasa (ruled 1523–60) centralized his administration and increased royal power over the nobility and the church. He built an extremely effi cient army and navy, both of them used frequently over the next century and a half. Hostilities and alliances among northern European powers shifted constantly, with the Danes and Swedes sometimes united – against the German city of Lübeck, and later against Emperor Charles V – and sometimes fi ghting against each other, as in the Northern War (1563–70), which involved major naval battles fought by specialized battleships and ultimately ended in Danish defeat. The Danish and Swedish royal houses were frequently linked by marriage to those of the rest of Europe – the Danish King Christian II married the sister of the Emperor Charles V, the brother of the king of Sweden married the daughter of the king of Poland–Lithuania – so that northern confl icts were often supported by money and troops coming from elsewhere.