Sigismund I, 1467–1548, king of Poland (1506–48), son of Casimir IV. Elected to succeed his brother, Alexander I, Sigismund faced the problem of consolidating his domestic power in order successfully to counter external threats to Poland. The enactment (1505) during Alexander's rule of the law Nihil Novi, which forbade the kings to enact laws without the consent of the diet, seriously handicapped Sigismund in his struggle with the magnates and nobles. Nevertheless, he established (1527) a regular army and a fiscal system to finance its maintenance. Intermittent war with Vasily III of Moscow began in 1507; in 1514 Smolensk fell to the Muscovite forces. In 1515 Sigismund entered an alliance with Holy Roman Emperor Maximilian I. Maximilian acknowledged the provisions of the Second Peace of Toruń, and Sigismund consented to the marriage of the children of his brother, Uladislaus II of Bohemia and Hungary, with the grandchildren of Maximilian. Through this double marriage contract Bohemia and Hungary passed to the house of Hapsburg on the death (1526) of Sigismund's nephew, Louis II. Sigismund's wars against the Teutonic Knights ended in 1525, when their grand master, Albert of Brandenburg, having converted to Lutheranism, secularized the order and did homage to Sigismund, who invested him with the domains of the order as the first duke of Prussia. Sigismund sought peaceful relations with the khans of Crimea but was still involved in border warfare with them. Sigismund was a humanist; he and his second wife, Bona Sforza, daughter of Gian Galeazzo Sforza of Milan, were patrons of Renaissance culture, which began to flower in Poland during their reign. He was succeeded by his son, Sigismund II.