HistoryData
war921

921 battle of the Byzantine-Bulgarian Wars

March 1, 0921

A decisive Bulgarian victory near Constantinople that exposed Byzantine military weakness and enabled Bulgarian dominance over Thrace in the early 920s.

Quick Facts

Year
921
Category
war

Key Facts

Date range
11–18 March 921
Location
Pegae, outskirts of Constantinople
Conflict
Byzantine–Bulgarian War of 913–927
Adrianople captured
922, following Bulgarian success at Pegae
Follow-up battle
June 922 Byzantine defeat near Constantinople
Primary sources
Theophanes Continuatus, John Skylitzes, Leo the Grammarian

By the Numbers

11
Date range
913
Conflict
922
Adrianople captured
922
Follow-up battle

Location

Map of Constantinople, Byzantine EmpireMap of Constantinople, Byzantine EmpireConstantinople, Byzantine Empire

Cause → Event → Consequence

Cause

The Bulgarian Empire under Simeon I had been waging an aggressive war against Byzantium since 913, seeking to expand Bulgarian control across Thrace and pressure Constantinople. By 921 Bulgarian forces had advanced to the outskirts of the Byzantine capital, bringing the two empires into direct confrontation near the locality of Pegae.

Event

Between 11 and 18 March 921, Bulgarian and Byzantine forces clashed at Pegae, a locality near Constantinople named after the Church of St. Mary of the Spring. The Byzantine lines collapsed at the first Bulgarian assault, commanders fled the battlefield, and most Byzantine soldiers were killed, drowned, or captured in the ensuing rout.

Consequence

The Bulgarian victory opened Thrace to further conquest; by 922 Bulgarians had captured Adrianople and Bizye and defeated another Byzantine army near Constantinople. Although Bulgaria lacked naval power to besiege the capital, its dominance over the Balkans was confirmed. A Bulgarian attempt to ally with the Fatimids for a joint assault on Constantinople was uncovered and neutralised by the Byzantines.

Belligerents & Mobilization Analysis

Side A

1 belligerent

Bulgarian Empire

Side B

1 belligerent

Byzantine Empire
Outcome
Decisive Bulgarian victory; Byzantine forces routed, most soldiers killed, drowned, or captured.

Timeline Context

Timeline around 921921918919920922923924battle-of-pegae-921