Every day in Bulgarian history holds a story worth remembering. In this recurring series, On This Day in Bulgaria, we look back at notable events, decisions, and milestones that happened on this date across the country’s history.
September 20, 917 — Battle of Achelous
In one of the grandest military engagements of the European Middle Ages, Bulgarian Tsar Simeon I the Great scored a decisive victory over the Byzantine Empire at the Achelous River (near modern-day Pomorie). The annihilation of the Byzantine army established Bulgaria as the dominant military power in Southeastern Europe.
September 20, 1944 — Bulgaria Declares War on Hungary
Following the change of government and shift to the Allied side, the new Bulgarian administration declared war on Hungary. Bulgarian military divisions were integrated into the Red Army’s 3rd Ukrainian Front, participating in the Belgrade Offensive and campaigns in Hungary and Austria to push German forces out of Southeastern Europe.
Explore more of Bulgaria’s story on Bronicable, including our Bulgaria From Above series and our guides to the best of Bulgaria.
