Of the approximately two to three thousand volumes of Byzantine literature that survive, only 330 consist of secular poetry, history, science and pseudo-science.[1] While the most flourishing period of the secular literature of Byzantium runs from the 9th to the 12th century, its religious literature (sermons, liturgical books and poetry, theology, devotional treatises, etc.) developed much earlier with Romanos the Melodist being its most prominent representative.[221]