De Ceremoniis
The concept of "porphyrogénnētos" (literally meaning "born in the purple") was known from the sixth century in connection with growing ideas of hereditary legitimacy, but the first secure use of the word is not found until 846. The term became common by the 10th century, particularly in connection with Emperor Constantine VII Porphyrogennetos (), and its use continued into the Palaiologan period. Constantine VII described the ceremonies which took place during the birth of a "porphyrogénnētos" boy in his work "De Ceremoniis aulae byzantinae".