Advance
Camp Followers
Warriors obviously make up the bulk of our armies, but no army can consist of fighters alone. Without the extra entourage of people transporting food and equipment for the army, it would not be able to feasibly go anywhere. By organizing and structuring these camp followers, we can greatly increase their usefulness and efficiency.
Advance tree
The game files don’t say where this goes: it has no requires, so the game places it in the 
Reformation tree itself.
Modifiers
Supply Limit+10%
Definitionin_game/common/advances/4_choices_mil.txt:230
232icon = global_supply_limit_modifier_advance_5
233for = mil