 Complete the following phrase:  This fragmentation allowed the Eastern Empire to resume its policy of playing off barbarians against each other, to stop any one tribe from becoming too powerful. It is almost certain that the Gepid king Ardaric came to an agreement with Marcian. Ardaric had formed a coalition of the Rugians, Sciri, Heruli, and his own Gepids, which he led against the remaining Hunnic confederation. Ardaric, alongside the Ostrogoth leaders Theodemir, Valamir and Videmir, decisively defeated Attilas oldest son, Ellac, at the 