The following may also be consulted: C. Gewoldus, _Defensio Ludovici IV. contra A. Bzovium_ (Ingolstadt, 1618); J. G. Herwartus, _Ludovicus IV. imperator defensus_ (Mainz, 1618); N. Burgundus, _Historia Bavarica sive Ludovicus IV. imperator_ (Ingolstadt, 1636). The best modern authorities are F. von Weech, _Kaiser Ludwig der Bayer und König Johann von Böhmen_ (Munich, 1860); S. Riezler, _Die literarischen Widersacher der Päpste zur Zeit Ludwigs des Bayern_ (Leipzig, 1874); C. Mühling, _Die Geschichte der Doppelwahl des Jahres 1314_ (Munich, 1882); R. Döbner, _Die Auseinandersetzung zwischen Ludwig IV. dem Bayern und Friedrich dem Schönen von Oesterreich_ (Göttingen, 1875); W. Altmann, _Der Römerzug Ludwigs des Bayern_ (Berlin, 1886); A. Chroust, _Beiträge zur Geschichte Ludwigs des Bayern und seiner Zeit_ (Gotha, 1877); K. Müller, _Der Kampf Ludwigs des Bayern mit der römischen Curie_ (Tübingen, 1879-1880); W. Preger, _Der Kirchenpolitische Kampf unter Ludwig dem Bayern_ (Munich, 1877); Sievers, _Die politischen Beziehungen Kaiser Ludwigs des Bayern zu Frankreich_ (Berlin, 1896); Steinberger, _Kaiser Ludwig der Bayer_ (Münich, 1901); and Ueding, _Ludwig der Bayer und die niederrheinischen Städte_ (Paderborn, 1904). (A. W. H.*) LOUIS (804-876) surnamed the "German," king of the East Franks, was the third son of the emperor Louis I. and his wife Irmengarde. His early years were partly spent at the court of his grandfather Charlemagne, whose special affection he is said to have won. When the emperor Louis divided his dominions between his sons in 817, Louis received Bavaria and the neighbouring lands, but did not undertake the government until 825, when he became involved in war with the Slavonic tribes on his eastern frontier. In 827 he married Emma, daughter of Welf I., count of Bavaria, and sister of his stepmother Judith; and he soon began to interfere in the quarrels arising from Judith's efforts to secure a kingdom for her own son Charles, and the consequent struggles of Louis and his brothers with the emperor Louis I. (q.v.). When the elder Louis died in 840 and his eldest son Lothair claimed the whole Empire, Louis in alliance with his half-brother, king Charles the Bald, defeated Lothair at Fontenoy on the 25th of June 841. In June 842 the three brothers met on an island in the Sâone to negotiate a peace, and each appointed forty representatives to arrange the boundaries of their respective kingdoms. This developed into the treaty of Verdun concluded in August 843, by which Louis received the bulk of the lands of the Carolingian empire lying east of the Rhine, together with a district around Spires, Worms and Mainz, on the left bank of the river. His territories included Bavaria, where he made Regensburg the centre of his government, Thuringia, Franconia and Saxony. He may truly be called the founder of the German kingdom, though his attempts to maintain the unity of the Empire proved futile.