The heiress of Tirol, Margaret Maultasch, quarrelled with her husband, John Henry, margrave of Moravia, and fled to the pro tection of Louis, who seized the opportunity to declare her mar riage void and to unite her in 1342 with his son Louis. The em peror also increased his possessions by his own marriage. In 1322 his first wife, Beatrice, daughter of Henry III., count of Glogau, had died and by his second marriage with Margaret, daughter of William III., count of Holland, he obtained, at the death of her brother, count William IV., in 1345, possession of Holland, Zealand and Friesland. In 1341 he recovered a por tion of the Palatinate, and soon deserted Edward of England and came to terms with Philip of France. In the course of a war between Louis and the enemies made by his policy of acquisition which ensued in Germany he was forced to submit to humiliating terms, though he would not accept the election of Charles, mar grave of Moravia (afterwards the emperor Charles IV.) as Ger man king in July 1346. Charles consequently attacked Tirol; but Louis died suddenly at a bear-hunt near Munich on Oct. it, He was buried in the Frauenkirche at Munich, where a statue was erected to his memory in 1622 by Maximilian I., elector of Bavaria, and where a second was unveiled in 1905. He had seven sons, three of whom were subsequently electors of Brandenburg, and ten daughters.
As a soldier Louis possessed skill as well as bravery, but he lacked perseverance and decision in his political relations; and the fact that he remained almost undisturbed in the possession of Germany in spite of the utmost efforts of the popes, is due rather to the political and intellectual tendencies of the time than to his good qualities. He encouraged trade and commerce and gave a new system of laws to the duchy.
of the authorities for the life and reign of Louis are found in the Fontes rerum Germanicarum, Bande i. and iv., edited by J. F. Bohmer (Stuttgart, 1843-68). Among these is the Vita Ludovici IV., by an unknown author. A number of important documents are found in the Regesta imperii ed. J. F.
Bohmer and J. Ficker (Innsbruck, 1865) ; Acta imperii selecta, ed. J. F. Bohmer and J. Ficker (Innsbruck, 187o) ; Urkunden zur Gesch ichte des Romerzuges Konigs Ludwigs des Bayern, ed. J. Ficker (Inns bruck, 1865) ; Urkundliche Beitrdge zur Geschichte Kaisers Ludwigs IV., ed. C. Hofler (Munich, 1839) ; Vatikanische Urkunden zur Ge schichte Kaisers Ludwigs des Bayern, Bande v. and vi. (Stuttgart, 1877-88) ; Vatikanische Akten zur Deutschen Geschichte in der Zeit Kaisers Ludzvigs des Bayern, ed. S. Riezler (Innsbruck, 1891). In the Forschungen zur Deutschen Geschichte (Gottingen, 1862-86), Band. xx., is found Urkunden zur Bairischen und Deutschen Geschichte ed. S. Riezler; and in Band xiii. is C. Hautle's Beitrdge zum ltinerar Kaiser Ludwigs.
The following may also be consulted: C. Gewoldus, Defensio Ludovici IV. contra A. Bzovium (Ingolstadt, 1618) ; J. G. Herwartus, Ludovicus IV. imperator defenses (Mainz, 1618) ; N. Burgundus, Historia Bavarica sive Ludovicus IV. imperator (Ingolstadt, 1636). The best modern authorities are F. von Weech, Kaiser Ludwig der Bayer and Konig Johann von &Amen (Munich, 186o) ; S. Riezler, Die literarischen Widersacher der Piipste zur Zeit Ludwigs des Bayern (Leipzig, 1874) ; C. Maling, Die Geschichte der Doppelwahl des Jahres 1314 (Munich, 1882) ; R. Dobner, Die Auseinandersetzung zwischen Ludwig IV. dem Bayern und Friedrich dem Schonen von Oesterreich (Gottingen, 1875) ; W. Altmann, Der Romerzug Ludwigs des Bayern (1886) ; A. Chroust, Beitrdge zur Geschichte Ludwigs des Bayern und seiner Zeit (Gotha, 1877) ; K. Muller, Der Kampf Ludwigs des Bayern mit der romischen Curie (Tubingen, 1879-80) ; W. Preger, Der Kirchenpolitische Kampf enter Ludwig dem Bayern (Munich, 1877) ; Sievers, Die politischen Beziehungen Kaiser Ludwigs des Bayern zu Frankreich (1896) ; Steinberger, Kaiser Ludwig der Bayer (Munich, 1901) ; and Ueding, Ludwig der Bayer und die niederrheinischen Stiidte (Paderborn, 5904).