The army is also changing its base unit from divisions to brigades. Division lineage will be retained, but the divisional headquarters will be able to command any brigade, not just brigades that carry their divisional lineage. The central part of this plan is that each brigade will be modular, i.e., all brigades of the same type will be exactly the same, and thus any brigade can be commanded by any division. As specified before the 2013 end-strength re-definitions, the three major types of ground combat brigades are: