How Tervel Turned a Deposed Emperor Into Bulgaria's Partner

The Challenge

At the start of the eighth century Bulgaria was a young state beside a far larger empire. Tervel needed recognition, territory and security, and in 704 an opportunity arrived: the deposed Byzantine emperor Justinian II, exiled and mutilated, came asking for help to regain his throne.

The Approach

• Backed Justinian II with an army, and in 705 helped him retake Constantinople
• Was rewarded with the title of Caesar, the first foreign ruler to receive it, along with territory south of the Balkan mountains
• When Justinian turned against him and attacked in 708, defeated him at Anchialus
• In 716 Bulgaria concluded a treaty with Emperor Theodosius III that fixed the border and regulated trade; Theophanes names Kormesios as the Bulgarian ruler who signed it, possibly on Tervel's authority
• In 717–718 sent his army against the Arabs besieging Constantinople; Theophanes puts the Arab dead at about 22,000

The Impact

Bulgaria gained prestige, land and a formal place in Byzantine diplomacy. Its help against the Arab siege, one of the decisive events of the age, earned it standing as a partner the empire could not ignore.

The 708 war showed the limits of a personal alliance: the emperor Tervel had restored became his enemy within three years.

The Lesson for Leaders

Backing the right partner at the right moment can buy decades of standing. But alliances built on one person's gratitude are fragile; Bulgaria's lasting gains came from formal agreements, like the treaty of 716, that bound the empire as an institution rather than a single ruler.