Huns on the run, never ending battle

[rebelscum]

I began a Sarmatian campaign today with a single small village to my name. Knowing the huns were closing in I moved a good stack of units away into goth territory. I left two vigin horsewomen two generals and a spear unit inside.
The remaining defenders routed the first horde single stack. The next turn I was hit on all 4 sides and my faction leader and his son were killed.
Up pops my horde over the bridge on the campaign map.
The next turn I clashed with the first horde stack vs two of mine.
I made mincemeat of them due to their poor tactics trying to get heavy cav over the bridge hitting my spears whilst I shot everything else up with the missile cav. When they sent in the spear units I used my swords in to take care of them. After their inital charge they seemed hesitant, lining up their units for a bridge crossing but not moving. I goaded them on by moving my spear units back and they began a charge with the rest, infantry over the bridge and their missile and remaining cav over the water.
When they routed I was quite pleased as any remaining units ran back into the approaching AI general and his stack.
As soon as the battle finished a second began, my two stacks vs one.
It was a complete re-run on the first battle and it left me a little worn down by pretty much still a fighting force.
As soon as that battle finished another one started. Another re-run and I won it rather easily as I had the system down pat this time.
So now the hun horde is down to half their original size and I have about 3 full stacks. If I wait across the bridge I think I can pretty much destroy the entire hun horde. What happens then? Do they re-appear and do the same again, if so I dont think I could put up with the tedium.