In OTL, after the death of Attila, the Hunnic Empire fragmented with the Huns' former vassals breaking free and the various tribes that had constituted the Huns splitting apart, and eventually disappearing into the realm of history. Now, without any POD's before the 5th Century, how can Attila's empire survive at least long enough to for a Hun state to remain in Europe for a significant period of time and leave a more noticeable mark. How does the course of European history form with some sort Hunnic nation remaining in the eastern part of the continent? Also, could Attila come to finally sack Rome if he wins at Chalons or alternatively doesn't die in 453 of a fatal nosebleed?