porphyrogenitism noun1 •(rare) The principle of succession in royal families, especially among the Eastern Roman emperors, by which a younger son, if born after the accession of his father to the throne, was preferred to an elder son who was born prior to it.The doctrine of Porphyrogenitism, congenial to popular sentiment, and not without some foundation in principle, prevailed influentially and widely in many countries. — 1851
