Great Moravia
In 861 Khan Boris concluded an alliance with East Frankish King Louis the German, all while informing him that he would like to accept Christianity according to western rite. This renewed alliance threatened Great Moravia, which sought help from Byzantium (862–863). This was at the same time when a Byzantine mission to Great Moravia was taking place. Cyril and his brother Methodius intended to draw Great Moravia closer to Constantinople and strengthen the Byzantine influence there.