The battle took place following a series of Arab raids around Gaza. The Byzantine commander (dux and candidatus) Sergius assembled a small detachment of soldiers (due to shortness of troops), and led that mounted army from his base at Caesarea some 125 kilometers south to the vicinity of Gaza. From there he proceeded against an Arab force that was likely numerically superior and commanded by Abu Umamah al-Bahili. The opposing forces met at the village of Dathin on February 4, 634 AD, not far from Gaza. The Byzantine were defeated and the candidatus Sergius himself was killed, together with 300 of his soldiers.
^Kaegi, pp. 90-93. Al-Tabari, p. 108, and al-Baladhuri, pp. 167-68, do not name the Byzantine commander, referring to him only by the general rank of patrician (baṭrīq). Theophanes, p. 37, names Sergius, but does not specify the location of the battle and dates it to 632-633 AD.
Le Strange, Guy. Palestine Under the Moslem: A Description of Syria and the Holy Land, From A.D. 650 to 1500. London: A. P. Watt, 1890.
Al-Tabari, Abu Ja'far Muhammad ibn Jarir. The History of al-Tabari, Volume XI: The Challenge to the Empires. Trans. Khalid Yahya Blankinship. Ed. Ehsan Yar-Shater. Albany, NY: State University of New York Press, 1993. ISBN 0-7914-0851-5