The dynatoi (Greek: δυνατοί, "the powerful") was a legal term in the Byzantine Empire used from the 10th century on, denoting the senior levels of civil, military and ecclesiastic (including monastic) officialdom, who usually, but not always, also commanded considerable fortunes and landed estates. Although such positions were not usually hereditary, by the late 10th and early 11th centuries they had started to become monopolized by a limited number of families who by the mid-11th century formed a hereditary aristocracy.[1]