In 874 the Mojmir duke Svatopluk I reached an agreement with the East Frankish king Louis the German and confirmed his Bohemian dominion.[4] With the fragmentation of Great Moravia under the pressure of the Magyar incursions around 900, Bohemia began to form as an independent principality. Already in 880, the Přemyslid prince Bořivoj from Levý Hradec, initially a deputy of Duke Svatopluk I who had been baptised by the Great Moravian archbishop Methodius of Salonica in 874, moved his residence to Prague Castle and started to subjugate the Vltava Basin.