On 20 August 917 the army of Simeon I of Bulgaria routed a large Byzantine army under Leo Phokas by the river Achelous, near the fortress of Anchialus, today Pomorie on Bulgaria's Black Sea coast. The battle is also called the Battle of Achelous. Byzantine accounts say the imperial army began well and then fell apart, and the fleeing troops were cut down in great numbers. It was one of the heaviest defeats the empire ever suffered, and it left Simeon free to threaten Constantinople itself for years.
A tsar who wanted Constantinople
Simeon had been educated in Constantinople and came to the Bulgarian throne in 893. Britannica describes his dominant ambition as taking the imperial throne of Byzantium for himself, which drew him into war with the empire again and again, in 894, 896, 913, 917 and 923. The Byzantinist Alexander Vasiliev wrote that between the death of Emperor Leo VI in 912 and Simeon's death in 927 there was almost continuous warfare between the two states, and that Simeon very definitely strove to conquer Constantinople.1
In 917 the empire, governed in the name of the child emperor Constantine VII, went to war again. The empire tried to raise allies against Simeon among the peoples beyond the Danube, and a Byzantine army under Leo Phokas, carried by the fleet, landed at Anchialus. Our full article on the Battle of Anchialus tells the background in more detail.2
The battle by the Achelous
No detailed account of the fighting survives, and the size of the armies is unknown. Plamen Slavov, director of the archaeological museum at Veliki Preslav, has pointed to the Arab chronicler al-Masudi's figures of 62,000 Byzantines against 60,000 Bulgarians; a modern estimate summarized by the Balkan Military History site puts the Byzantine army at perhaps 30,000.3
As the course of the battle is usually reconstructed, the Byzantines attacked first and drove part of the Bulgarian army back toward the hills, but then lost their order, perhaps because of a rumor that Leo Phokas had been killed. Simeon counterattacked, the Byzantine advance stopped, and the retreat turned into a rout in which the imperial troops were slaughtered. Leo Phokas escaped. The historian Mirosław Leszka notes that the Byzantine writer Leo the Deacon put the defeat down not to Simeon's skill but to discord in the Byzantine camp.4
Heaps of bones
Leo the Deacon, writing at the end of the 10th century, recorded that even in his day heaps of bones could be seen near Anchialus, where the fleeing Roman army had been ingloriously cut down. Vasiliev writes that Byzantine losses in the wars with Simeon were especially severe in 917, when the imperial army was annihilated at the Achelous.5
The date is that of the Julian calendar used at the time. Bulgaria still marks the anniversary of the battle on 20 August, according to the Bulgarian News Agency.6
After Anchialus
After the battle, Vasiliev writes, the road to Constantinople lay open to Simeon. His armies were drawn into Serbia in 918, but in the following years they reached the Dardanelles, took Adrianople in 922 and burned imperial palaces outside the capital's walls; all of Thrace and Macedonia except Constantinople and Thessalonica fell into Bulgarian hands. Simeon took the title of tsar of all the Bulgarians, but he never captured Constantinople and died in 927.7
The balance swung back only in the next century, when Basil II broke Bulgarian power, a story told in our article on the Battle of Kleidion.
Also on this day
- 1710: Battle of Saragossa. Near Zaragoza, the Bourbon Spanish army of the Marquis de Bay was badly beaten by Guido Starhemberg's allied forces in the War of the Spanish Succession.
