Mount & Blade Cavalry vs 300 infantries

This is a 50 renown battle where i basically had around 80 soldiers against globally 900 enemies and my battle size lead me to fight 300 enemies per battles. At the end of this I had to fight more enemies in an other battle, but let say that I choosed to take my 50 renown bonus from that victory and retreat to my nearby castle where I had a good 84 garrison forcing the enemies to ignore me as a target and allowing my weaken army (and heavily wounded soldiers) to recover.