Units breaking immediately

Playing as the Romani, I engaged a Boii force. I have no chance to beat them because my entire army, including the commander, decides to route before even seeing the enemy. They just all break and leave the battle as soon as I'm finished deploying.

I think the closest we've gotten to an explanation for this is that you have a general with negative morale. Are you using one without Imperium, who doesn't have any traits or ancillaries that boost troop morale?

He has Imperium. However I don't think he has any other traits