On August 20, 917, the Bulgarian troops, led by Tsar Simeon I, defeated the Byzantine troops in the Battle of Acheloy. The battle was provoked by Byzantium, whose main goal was to neutralize the growing Bulgarian state after the humiliating conditions for Byzantium, achieved in 913. It was then that Prince Simeon was recognized with the title of “King of the Bulgarians”.
Empress Zoe and the rulers of Constantinople decided to defeat Tsar Simeon once and for all. First, they concluded a peace treaty with the Arabs and secured their support, and then they tried to build an anti-Bulgarian alliance. The strategist of Kherson, John Vogas, was sent to attract the Pechenegs, who would be transferred across the Danube by the Byzantine fleet to strike the Bulgarians in the rear. And the strategist of Durrës, Leo Ravnukh, tried to incite the Serbian prince Petar Gojnikovich and through him the Magyars against Simeon. The goal was to strike Bulgaria simultaneously from all sides.
The prince of Zakhulm, Mikhail Vishnevich, warned Simeon about the moves of Leo Ravnukh, and he managed not only to prevent the Roman-Hungarian alliance, but also to make his recent northern enemy an ally. The diplomatic battle to attract the Pechenegs was also won by the Bulgarian king, who had foresight established his first alliance with them back in 896.
The battle left an indelible memory among the Byzantines (according to Leo the Deacon, who lived 50 years after the battle, “heaps of bones can still be seen at the Aheloy River, where the Roman army was then ignominiously slaughtered”).
This victory also had an important psychological effect on the Byzantine army, which, seeing that it was losing the battle, fled. In a desperate attempt to stop the Bulgarians on their way to Constantinople, the Byzantines gathered the remnants of their army near the village of Katasirti and were again defeated in a night battle.
For the first time in Bulgarian history, at the initiative of Tsar Simeon I, the blessing of water was performed on the Bulgarian battle flags before the battle of the Aheloy River.
Later, the ritual began to be performed every year on Epiphany (Yordanovden), and not only before a battle. The tradition was restored in 1880 by the first Minister of War after the Liberation, Pyotr Parensov. After an interruption in 1946, the tradition was resumed on January 6, 1992.