Literature flourished especially during the reign of Emperor Zara Yaqob. Written by the Emperor himself were "Matsʼhafe Berhan" ("The Book of Light") and "Matshafe Milad" ("The Book of Nativity"). Numerous homilies were written in this period, notably "Retuʼa Haimanot" ("True Orthodoxy") ascribed to John Chrysostom. Also of monumental importance was the appearance of the Geʽez translation of the Fetha Negest ("Laws of the Kings"), thought to have been around 1450, and ascribed to one Petros Abda Sayd — that was later to function as the supreme Law for Ethiopia, until it was replaced by a modern Constitution in 1931.