2 militia Hoplites, one of the units above them for Macedon (levy pikeman?), and a peasant, not experienced, not teched up, was my garrison in one of my border cities between me and my Briton allies. The Britions decided to betray me, sent a 15 stack army to attack the city. I couldn't send any reinforcements, so the Britons ended up assaulting me with 8 rams. I had the lowest level of wooden wall as defence. No general. Their general had 4 stars. The odds were somewhere around 1 to 20.

I won. I never realized that peasants can actually be decent at flanking. I guess you realize these things when you're forced to use them.