Martyrology was the most popular literature in the early Church.
He also undertook a new edition to the Roman martyrology (1586), which he purified of many inaccuracies.
In the literature as it survives many different branches of writing are represented - homilies in prose and verse, hymns, exposition and commentary, liturgy, apocryphal legends, historical romance, hagiography and martyrology, monastic history and biography, general history, dogmatics, philosophy and science, ecclesiastical law, &c. But the whole is dominated by the theological and ecclesiastical interest.
The list of anniversaries of a church formed its Martyrology.
In the oldest Roman ferial we already find festivals of Carthaginian martyrs, and similarly, in the Carthaginian calendar, Roman festivals, while Wright's Syriac Martyrology contains numerous traces of this exchange of festivals.