Being a Byzantine chronicle, it follows familiar sources. From 600 to 627, that is, for the last years of the Emperor Maurice, the reign of Phocas, and the first seventeen years of the reign of Heraclius, the author is a contemporary historian, and his narrative is in every way quite interesting.
Like all Byzantine chroniclers, and unlike the more August historians, the author of this popular account relates anecdotes, the physical descriptions of the chief personages, which at times are careful portraits, extraordinary events, such as earthquakes and the appearance of comets, seen from the point of view of church history, with which the chronological plan of the Bible was made to agree. The idiom used was that of common life, little polished, but finically ornate. Sempronius Asellius points out this difference in the public appealed to and in the style of composition which distinguished the chroniclers (Annales) from the historians (Historia) of the Eastern Roman Empire.
The "Chronicon Paschale" is a huge compilation resulting in a chronological list of events from the creation of Adam; the principal manuscript, the 10th-century Codex Vaticanus græcus 1941, is damaged at the beginning and end and stops short at AD 627. The chronicle proper is preceded by an introduction which contains some reflections on Christian chronology and on the calculation of the Paschal cycle. The so-called Byzantine or Roman era (which continued in use in the Greek Church until its liberation from Turkish rule) was adopted in the Chronicum for the first time as the foundation of chronology, in accordance with which the date of the creation is given as the 21st of March, 5507. The author is merely a compiler from earlier works.
The author identifies himself as contemporary of the Emperor Heraclius (610-641), and was probably a cleric attached to the suite of the œcumenical Patriarch Sergius. The work was probably written during the last ten years of the reign of Heraclius.
The chief authorities used were: Sextus Julius Africanus; the consular Fasti; the Chronicle and Church History of Eusebius; John Malalas; the Acta Martyrum; the treatise of Epiphanius, bishop of Constantia (the old Salamis) in Cyprus (fl. 4th century), on Weights and Measures.