That same leader, Svatopluk I, aided Aribo in a rebellion in the March of Pannonia, the Wilheminer War, and it was under Svatopluk that this state achieved its greatest size.
The Annals of Fulda claims that both Louis the German and Charles the Fat invaded this polity, but only succeeded in raiding the countryside, being unable to dislodge its ruler from his castle. Pope John VIII issued the bull Industriae tuae in support of a ruler of this state, calling him "the only son", a term previously reserved for emperors. That same leader, Svatopluk I, aided Aribo in a rebellion in the March of Pannonia, the Wilheminer War, and it was under Svatopluk that this state achieved its greatest size. One ruler of this polity brought (*) Saints Cyril and Methodius to his court, leading to the first alphabet for a Slavic language, Glagolitic. For 10 points, name this 9th century state, the grander predecessor to a Czech region with capital at Brno.
The Annals of Fulda claims that both Louis the German and Charles
Great Moravia