peace. Two years later, the Bohemian king made a last attempt to recover his lost lands by force. Přemysl Ottokar again found allies in Bavaria, Brandenburg and Poland. He collected a large army to meet the forces of Rudolf and his ally King Ladislaus IV of Hungary in the Battle on the Marchfeld on 26 August 1278, where he was defeated and killed. Rudolf had his body laid out in state at the Minorites Church in Vienna. (In 1297 Ottokar's mortal remains were finally transferred to St. Vitus Cathedral in Prague.) His 6-year-old son Wenceslaus II succeeded him as King of Bohemia. Marriage and children On 11 February 1252, Přemysl Ottokar II married Margaret of Austria. Margaret was 26 years older than he, and the couple's childless marriage ended with an annulment. On 25 October 1261, Ottokar married Kunigunda of Slavonia. They probably had four children: Henry (1262–1263) Kunigunde (January 1265 – 27 November 1321), married Boleslaus II of Masovia Agnes (5 September 1269 – 17 May 1296), married Rudolf II, Duke of Austria Wenceslaus II (17 September 1271 – 21 June 1305) Ottokar also had two extramarital sons and daughters. The most important was his firstborn, Nicholas. He was never accepted as heir apparent to the Bohemian crown by the sitting pope, but was given the Duchy of Opava as fief in 1269. Other illegitimate children include John, provost of Vyšehrad Chapter. Legacy Přemysl Ottokar is considered one of the greatest kings of Bohemia, along with Charles IV. He was a founder of many new towns (about 30 — not only in Bohemia, Moravia and Silesia, but also in Austria and Styria) and incorporated many existing settlements through civic charters, giving them new privileges. He was a strong proponent of trade, law and order. Furthermore, he instituted open immigration policies through which skilled German-speaking immigrants settled in major cities throughout his domains. As noted, the historic East Prussian city of Königsberg (King's Mountain) was named in his honor as a tribute to his support of the Teutonic Knights in their war with the pagan Old Prussians. As Czech traditional law was different from that of his other domains, many principles introduced during his reign formed core of the Czech law for the following centuries. From his time stems the oldest preserved source of Czech law, Zemské desky, and also the oldest written Czech communal law, recorded in the founding