and Pribina fell out, and the latter, fearing for his life, fled with his son Koceľ to the First Bulgarian Empire. However, Malamir of Bulgaria had by that time made peace with East Francia, thus Pribina was unable to persuade him to act against the Franks. Subsequently, Pribina departed for Lower Pannonia, the region ruled by a Slavic prince, Ratimir. Since Lower Pannonia was part of Ratpot's prefecture, Ratimir's harboring of Pribina was tantamount to rebellion. Therefore, in 838 Louis the German sent Ratpot at the head of a large Bavarian army to crush Ratimir, but Pribina and his followers took refuge with the count of Carniola, Salacho. In short time the latter brokered a reconciliation between Ratpot and Pribina. Louis the German now devised a plan to solve the ongoing instability in Lower Pannonia by making Pribina himself the new client ruler of that region. On January 10, 846, at the request of his followers, the king granted Pribina lands near Lake Balaton on the river Zala where he was to rule as Louis the German's faithful dux ("duke"). Dux in Lower Pannonia Pribina's main duty was to gather the groups of Slavs who were fleeing from various directions, and to keep them loyal to the Franks. For this purpose, he began to build in 846 a large fortress as his seat of power in the region of Lake Balaton, in a territory of modern Zalavár surrounded by forests and swamps along the river Zala. His extremely well fortified castle that became known as Blatnohrad (Blatnograd) or Moosburg ("Swamp Fortress") served as a bulwark both against the Bulgarians and the Moravians. Pribina's authority stretched from the Rába river to the north, to Pécs to the southeast, and to Ptuj to the West. Pribina undertook to Christianize the local population and built churches in the region. At his request, the archbishop of Salzburg consecrated a number of churches in Lower Pannonia, among them one at modern Pécs. Pribina also made a donation of three hundred homesteads and vineyards on a knee of the river Zala to the monastery of Niederaltaich, which was confirmed in 860 by Louis the German. Pribina seems to have played a prominent role in Louis the German's campaigns against Mojmir I of Moravia. For example, in 846 the king made a generous gift of one hundred homesteads in the Bavarian marches to him, presumably in order