Battle in Illyricum, 551

In 551, tensions between the Germanic Gepid and Lombard peoples in Pannonia intensified considerably. The Gepids appealed to the Kutrigurs for military assistance, and they sent an army of 12,000 men under their chief Chinialon. This force arrived early, before the agreement between the Gepids and Lombards had expired, prompting the Gepids to persuade the Kutrigurs to attack Illyricum and Thrace.

To overcome this danger, the Byzantine emperor divided the Bulgar tribal confederations. He bestowed riches on the Utigur chief Sandil and provided him with the support of 2,000 Gothic soldiers. With his superior forces, Sandil crossed the Don River and fought the Kutrigur tribes.

Sandil routed the Kutrigur tribes and enslaved them, carrying their women and children back to his lands. The war also enabled Byzantine prisoners of war escaping from Kutrigur territory to return home. This devastating Utigur campaign forced one Kutrigur tribe under the chief Sinnion to seek refuge and a new place to settle in the Balkan Peninsula. With the Byzantine emperor's consent, the tribe settled in Thrace near the fortress of Apri. This, however, angered Sandil, leader of the Utigur military-tribal confederation, who expressed his displeasure to the emperor through his envoys.