The Umayyad army was led by Muhammad ibn Marwan, brother of the Caliph, and included the minister of defense, the famously known Al-Hajjaj ibn Yusuf. The Byzantines were led by Leontios and included a "special army" of 30,000 Slavs under their leader Neboulos. The Umayyads, incensed at the breaking of the treaty, used copies of its texts in the place of a flag. Though the battle seemed to be tilting to the Byzantine advantage, the defection of upwards of 20,000 Slavs ensured a Byzantine defeat. One source states that the Emperor Justinian II massacred the remaining Slavs, including women and children, at the Gulf of Nicomedia, yet modern scholars do not consider this a reliable account.
Hendy, Michael F. (2008). Studies in the Byzantine Monetary Economy C. 300-1450. Cambridge University Press.
Lilie, Ralph-Johannes (1976), Die byzantinische Reaktion auf die Ausbreitung der Araber. Studien zur Strukturwandlung des byzantinischen Staates im 7. und 8. Jhd. (in German), Munich: Institut für Byzantinistik und Neugriechische Philologie der Universität München
Stratos, A.N. (1980), Byzantium in the Seventh Century, Volume V: Justinian II, Leontius and Tiberius, 685–711, Amsterdam: Adolf M. Hakkert, pp. 34–38, ISBN90-256-0852-3