Society of the Byzantine Empire

Plethron (, plural plethra) is an ancient Greek unit of measurement equal to 97 to 100 Greek feet (ποῦς, pous; c. 30 centimeters), although the measures for plethra may have varied from polis to polis. This was roughly the width of a typical ancient Greek athletic running-track.

The dynatoi (, sing. Δυνατός, Dynatos "the powerful") was a legal term in the Byzantine Empire, 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.

local council that rejected the Union of the Churches at Lyons