Svatopluk I of Moravia
Towards the Peace of Forchheim

Carloman soon came to the conclusion that the accusations against Svatopluk were unfounded and released him from prison. In order to bind Svatopluk to his family, Carloman had Svatopluk stand as godfather to his illegitimate grandson. Thus this son of Carloman's son Arnulf received the Moravian name Zwentibold.

Svatopluk also agreed to lead Carloman's armies against Slavomír and the rebellious Moravians. However, on his arrival at "Rastislav's old city", Svatopluk betrayed the Bavarians and conspired secretly with the rebels. Although he captured the fortress in accordance with Carloman's plan, once he was inside its walls he renounced his loyalty to Carloman, rallied a large Moravian force and launched a devastating surprise attack on the unsuspecting Bavarian army encamped outside. The Moravians took a great number of soldiers hostage, killed the rest and rid Moravia of the Frankish occupation. Carloman's governors, William and Engelschalk, were also both slain, and Svatopluk became the undisputed ruler of Great Moravia.

Meanwhile Zwentibald, after no one had been able to prove the crimes of which he had been accused, was released by Carloman and returned to his own realm laden with kingly gifts, leading with him an army of Carloman's, with which he was to drive out Sclagamar, for so much he had falsely promised to Carloman, should Carloman allow him to return to his country. But just as humiliation falls on those who are careless and trust too much in themselves, so it befell that army, for Zwentibald left the others to pitch camp and entered the old city of Rastiz. Immediately he denied his fidelity and forgot his oath, in Slavic fashion, and turned his thought and his powers not to driving out Sclagamar but to revenging the injury which Carloman had done him. Then he attacked in great force the Bavarians' camp – they suspected no evil and were not keeping a sharp watch. He took many alive as prisoners, and killed the rest, except for a few who had prudently left the camp beforehand. All the Bavarians' joy at their many previous victories was turned into grief and weeping. On the news of the slaughter of his army, Carloman was aghast, and forced by necessity he ordered all the hostages in his kingdom to be collected together and returned to Zwentibald; he received scarcely one man from there except for a man called Radbod who returned half-dead.

In October 871 Louis the German sent Bavarian and Franconian troops against the Bohemians (Czechs). During the campaign the Franconians surprised a party of Moravians somewhere near the traps that guarded the narrow approaches to a Bohemian fort. The Moravians were returning to their homeland with the daughter of a Bohemian dux ("duke"), presumably to marry an unidentified Moravian magnate. Although the Moravians managed to reach the safety of the fort, they had to abandon 644 fully equipped horses in the narrows. The marriage of a Bohemian leader's daughter to a Moravian magnate implies that Svatopluk was planning to form an alliance with the Bohemians.

Louis the German realized the grave threat posed by Svatopluk and assembled forces for a multipronged expedition with pincer movements advancing on Moravian territory from several directions in 872. One army was sent out "against the Moravian Slavs" from Regensburg (Germany) in May, but the Thuringian and Saxon soldiers fled in their first encounter with the enemy. The second army, composed of Franconians under Bishop Arn of Würzburg and Abbot Sigihard of Fulda, experienced mixed results: although their forces fought well, the majority of the men were killed, and only a handful of survivors returned to East Francia. Finally a third force, consisting of Bavarians and Carantanians under Carloman's command, laid Moravian territories to waste, put Svatopluk's army to flight and forced it to take refuge in an "extremely well fortified stronghold". Svatopluk, however, soon assembled a large army and attacked the Bavarians who had been left behind under the command of Bishop Emriacho of Regensburg to guard ships on the bank of the river Danube.

In May 873, Pope John VIII moved energetically to discover the whereabouts of Methodius, who was still being held prisoner in Bavaria. He sent harshly worded letters to Carloman and the Bavarian bishops, and commanded Methodius's immediate reinstatement. The Pope seems also to have brokered a lasting peace between Louis the German and Svatopluk. After his meeting with the Pope at Verona (Italy), Louis the German went to Forchheim where, according to the Annals of Fulda, "he received the legates of Svatopluk asking for a peace treaty". The exact terms of their agreement are not known, but it seems to have been a compromise: Svatopluk was forced to make an annual payment of tribute to Louis the German, who agreed to avoid any hostile acts against Great Moravia. Thus Methodius, who had in the meantime been allowed to return to Moravia, could continue his work in relatively peaceful conditions for some years.
change_case:capital_word_frequency[3]