Justinian II
In 705 the Bulgarian Khan Tervel helped the ex-emperor of Byzantium Justinian II regain his throne after 10 years in exile. To show his gratitude, Justinian gave the Bulgarians an enormous quantity of gold, silver, and silk, as well as the "Zagore" area, located between Stara Zagora, Sliven, and the Black Sea. Three years later, Justinian II considered himself strong enough to invade Bulgaria and restore his rule over these lands.