Reign of Constantine VII
İstanbul, TurkeyMost of his reign was dominated by co-regents: from 913 until 919 he was under the regency of his mother, while from 920 until 945 he shared the throne with Romanos Lekapenos, whose daughter Helena he married, and his sons. Constantine VII is best known for the Geoponika, an important agronomic treatise compiled during his reign, and his four books, De Administrando Imperio, De Ceremoniis, De Thematibus, and Vita Basilii.