Svatopluk allied himself with the Franks and helped them seize Rastislav in 870. Carloman annexed Rastislav's realm and appointed two Frankish lords, William and Engelschalk, to administer it. Frankish soldiers arrested Archbishop Methodius on his way from Rome to Moravia at the end of the year. Svatopluk, who continued to administer his own realm after his uncle's fall, was accused of treachery and arrested by Carloman on Louis the German's orders in 871. The Moravians rose up in open rebellion against the two Frankish governors and elected a kinsman of Svatopluk, Slavomír, duke. Svatopluk returned to Moravia, took over command of the insurgents, and drove the Franks from Moravia. According to the Czech historian Dušan Třeštík, the rebellion of 871 led to the formation of the first Slavic state.