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.