as Byzantine military action against the initial Muslim invasions, Kaegi asserts that "Byzantine traditions ... attempt to deflect criticism of the Byzantine debacle from Heraclius to other persons, groups, and things". The range of non-historical Byzantine sources is vast: they range from papyri to sermons (most notable those of Sophronius and Anastasius Sinaita), poetry (especially that of Sophronius and George of Pisidia) including the Acritic songs, correspondence often of a patristic provenance, apologetical treatises, apocalypses, hagiography, military manuals (in particular the Strategikon of Maurice from the beginning of the 7th century), and other non-literary sources, such as epigraphy, archeology, and numismatics. None of these sources contains a coherent account of any of the campaigns and conquests of the Muslim armies, but some do contain invaluable details that survive nowhere else. See also Aegyptus (Roman province) Battle of Tours Byzantine–Ottoman Wars Byzantine–Seljuk wars Early Muslim conquests Spread of Islam Notes References Citations Sources Primary sources Ahmad ibn Yahya al-Baladhuri. Futuh al-Buldan. See a translated excerpt ("The Battle of Yarmouk and after") in Medieval Sources. Theophanes the Confessor. Chronicle. See original text in Documenta Catholica Omnia (PDF). Zonaras, Joannes, Annales. See the original text in Patrologia Graeca. Secondary sources Further reading External links Invasions of Europe Spread of Islam Wars involving the Byzantine Empire