For centuries, the Byzantine and Bulgarian Empires fought a relentless, high-stakes game of survival.
From the late 5th century until the fall of Constantinople, the Byzantine and Bulgarian Empires were locked in a volatile struggle for dominance. Through shifting alliances, brutal battlefield massacres, and complex diplomatic treaties, these two powers reshaped the Balkan Peninsula, testing the limits of imperial authority and cultural survival.
The conflict began in 499 AD when Bulgars defeated a 15,000-strong Roman force. By 681 AD, the Byzantine Emperor Constantine IV was forced to recognize the Bulgarian state in Moesia and pay protection money to prevent further incursions. This set a precedent for a relationship defined by shifting borders and uneasy truces. The 8th century saw intense volatility, including the 705 AD restoration of Justinian II, who rewarded the Bulgar ruler Tervel with the title of Caesar—the first time a foreign leader received such an honor—before later violating their agreements and suffering defeat at the Battle of Anchialus in 708 AD.
The 9th century brought even greater instability. In 811 AD, Emperor Nikephoros I captured the Bulgarian capital of Pliska, only to be killed in the Vărbica pass shortly after. Legend claims the Bulgar Khan Krum fashioned the emperor's skull into a silver-lined drinking cup. By 813 AD, Krum had forced three different Byzantine emperors to abdicate or flee. Later, in 917 AD, the Battle of Achelous became one of the largest clashes in medieval history, where Simeon I of Bulgaria decimated Byzantine forces, cementing his ambition to be recognized as Emperor of both Bulgarians and Romans.
The tide eventually turned in 1018 AD when Basil II conquered Bulgaria, ending the First Bulgarian Empire. Despite later rebellions and the rise of the Second Bulgarian Empire in 1185 AD, the geopolitical landscape remained fractured. The era of direct confrontation finally waned as external threats mounted. The cycle of fluctuating power between the two empires concluded only when the Ottoman Turks seized the Bulgarian capital in 1393 and eventually conquered Constantinople in 1453.
These wars were not merely territorial; they were existential. They involved complex religious conversions, such as Boris I’s baptism in 863 AD, and economic disputes, such as the 894 AD relocation of Bulgarian trade markets. The persistence of these conflicts highlights how deeply intertwined the two empires were, constantly oscillating between total war and fragile, treaty-bound peace.
Source: Byzantine–Bulgarian wars
