of Rome. Journey to Rome The mission of Constantine and Methodius had great success among Slavs in part because they used the people's native language rather than Latin or Greek. In Great Moravia, Constantine and Methodius also encountered missionaries from East Francia, representing the western or Latin branch of the Church, and more particularly representing the Carolingian Empire as founded by Charlemagne, and committed to linguistic, and cultural uniformity. They insisted on the use of the Latin liturgy, and they regarded Moravia and the Slavic peoples as part of their rightful mission field. When friction developed, the brothers, unwilling to be a cause of dissension among Christians, decided to travel to Rome to see the Pope, and seek a solution that would avoid quarreling between missionaries in the field. In 867, Pope Nicholas I (858-867) invited the brothers to Rome. Their evangelizing mission in Moravia had by this time become the focus of a dispute with Archbishop Adalwin of Salzburg (859–873) and Bishop Ermanrich of Passau (866-874), who claimed ecclesiastical control of the same territory and wished to see it use the Latin liturgy exclusively. Travelling with the relics of Saint Clement and a retinue of disciples, and passing through Pannonia (the Balaton Principality), where they were well received by Prince Koceľ. This activity in Pannonia made a continuation of conflicts inevitable with the German episcopate, and especially with the bishop of Salzburg, to whose jurisdiction Pannonia had belonged for seventy-five years. As early as 865, Bishop Adalwin was found to exercise Episcopal rights there, and the administration under him was in the hands of the archpriest Riehbald. The latter was obliged to retire to Salzburg, but his superior was naturally disinclined to abandon his claims. The brothers sought support from Rome, and arrived there in 868, where they were warmly received. This was partly due to their bringing with them the relics of Saint Clement; the rivalry with Constantinople as to the jurisdiction over the territory of the Slavs would incline Rome to value the brothers and their influence. New Pope Adrian II (867-872) gave Methodius the title of Archbishop of Sirmium (now Sremska Mitrovica in Serbia) and sent him back in 869, with jurisdiction over all of Moravia and Pannonia, and authorisation to use the Slavonic Liturgy. The brothers were praised for their learning and cultivated for their influence in Constantinople. Anastasius Bibliothecarius would later call Cyril "a