Loading up the game here:
The units were level 8 with 290 hp, 157 attack, 27 defense. They were using the lightning hammer (+1 attack per level) and a mix of plate+masterchain. I had 4 of them and a couple yewbowman. I think I managed to fight him in my territory though, so that was 180 attack, 34 defense.
To be perfectly honest I had no idea what I was getting myself into before the fight started. I would have arranged my army and champions differently if I was aware what was going to happen. If I had waited until the end of the techtree for champion armor or given them constituion instead of charge they would have been even stronger.
In any case 200 hp with your soveriegn is pretty boss. I couldn't even break 100 on mine without champion armor.