Zabergan (Medieval Greek: Ζαβεργάν) was the chieftain of the Kutrigurs, a nomadic people of the Pontic–Caspian steppe, after Sinnion. His name is Iranian, meaning full moon.^[1] Either under pressure from incoming Avars,^[2] or in revolt against the Byzantine Empire, in the winter of 558, he led a large Kutrigur army that crossed the frozen Danube. The army was divided into three sections: one raided south far as Thermopylae, while two others the Thracian Chersonesus and the periphery of Constantinople.^[3] In March 559 Zabergan attacked Constantinople, and one part of his forces consisted of 7,000 horsemen,^[4] but Belisarius defeated him at the Battle of Melantias and he was forced to withdraw.^[5]

The transit of such big distances in a short period of time shows that the Kutrigurs were mounted warriors,^[3] and Zabergan's raiders were already encamped near the banks of the Danube.^[3] However, once again Emperor Justinian I (r. 527–565) managed to persuade the Utigur chieftain Sandilch to attack the Kutrigurs, which resulted in the decimation of both.^[2] Nevertheless, according to the 12th-century chronicle of Michael the Syrian the remnant of those Bulgars were granted Dacia in the time of Maurice (r. 582-602).^[6] It is unknown if Zabergan was related to the Byzantine general named Zabergan, who in 586 defended the fortress Chlomaron against the Romans.^[1]