When an abbey becomes overlarge, or when there is need of a monastery in a new area, the abbot may appoint a group of monks under a prior to begin a new foundation, which remains a dependency of the mother abbey until such time as it is large and stable enough to become an independent abbey of its own.
When an abbey expands or when a monastery is needed in a new location, the abbot may assign monks under a prior to establish a new foundation that will eventually become self-sufficient and independent from the mother abbey.