Each side's War Minister, Prime Minister, and Monarch are authorized to merge that side's units. The CO or XO of the unit that is eliminated may also submit a merge order for his unit.
Infantry units may not be raised above 4000 men and one battery, cavalry units may not be raised above 2000 men and one battery, artillery may not be raised above 400 men and 4 batteries, and militia units may not be raised above 2000 men. If a merge order would violate these limits, the order is carried out, and the extra men and/or batteries are lost.