Armies and Parties in Mount & Blade II: Bannerlord
Parties belonging to a kingdom’s nobles and any hired mercenaries can be assembled together to form armies. Armies have an advantage over parties traveling separately, as their members will stick together and reinforce each other in battle. Most sieges in the game will need to be conducted by armies, as parties on their own are rarely large enough to take a major fortress.
The leader of an army summons other nobles by spending Influence. Each army has a cohesion statistic, which represents how motivated your commanders are and how well they work together. If an army’s cohesion falls below a certain threshold, it will be disbanded automatically. Armies start with average cohesion, and normally it drops a little bit each day the army stays in the field.
Parties are made up of troops and can travel around the map. generally, bigger parties are slower because they are more likely to lose marching order or get clogged in choke points. Parties that are overburdened by carrying too many goods also move more slowly.
Keeping a number of horses in your inventory may speed up your party considerably since they’ll increase your carrying capacity and footmen will ride spare horses. Pack horses and mules are only useful for carrying cargo though.