a state of concord." It was during this time that Otto first tried to link himself to the Eastern Empire through marriage negotiations. Slavic wars As Otto was finalizing actions to suppress his brother's rebellion in 939, the Slavs on the Elbe River revolted against German rule. Having been subdued by Otto's father in 928, the Slavs saw Henry's rebellion as an opportunity to regain their independence. Otto's lieutenant in east Saxony, Count Gero of Merseburg, was charged with the subjugation of the pagan Polabian Slavs. According to Widukind, Gero invited about thirty Slavic chieftains to a banquet; after the feast his soldiers attacked and massacred the unsuspecting drunken guests. The Slavs demanded revenge and marched against Gero with an enormous army. Otto agreed to a brief truce with his rebellious brother Henry and moved to support Gero. After fierce fighting, their combined forces were able to repel the advancing Slavs; Otto then returned west to subdue his brother's rebellion. In 941, Gero initiated another plot to subdue the Slavs. He recruited a captive Slav named Tugumir, a Hevelli chieftain, to his cause. Gero promised to support him in claiming the Hevellian throne, if Tugumir would later recognize Otto as his overlord. Tugumir agreed and returned to the Slavs. Due to Gero's massacre, few Slavic chieftains remained, and the Slavs quickly proclaimed Tugumir as their prince. Upon assuming the throne, Tugumir murdered his chief rival and proclaimed his loyalty to Otto, incorporating his territory into the German kingdom. Otto granted Tugumir the title of "duke" and allowed Tugumir to rule his people, subject to Otto's suzerainty, in the same manner as the German dukes. After the coup by Gero and Tugumir, the Slavic federation broke apart. In control of the key Hevelli stronghold of Brandenburg, Gero was able to attack and defeat the divided Slavic tribes. Otto and his successors extended their control into Eastern Europe through military colonization and the establishment of churches. Military expansion into Italy Disputed Italian throne Upon the death of Emperor Charles the Fat in 888, the empire of Charlemagne was divided into several territories: East Francia, West Francia, the kingdoms of Lower and Upper Burgundy, and the Kingdom of Italy, with each of the realms being ruled by its own king. Though the pope in Rome continued to invest the kings of Italy as "emperors" to rule Charlemagne's empire, these "Italian emperors" never exercised