Simon I (864-927) was a king of Bulgaria who reigned from 893 to 927. During the reign of Simon I, the country was at its peak with four attacks on Constantinople, including Albania and Serbia. Simon called himself the 'Emperor of Romans and Bulgarians'. After Simon, the First Bulgarian Empire gradually declined.

Family background
The Bulgars were originally a branch of the Turkic tribes in Central Asia, and arrived in Eastern Europe during the Great Migration of Nations in the 4th and 5th centuries. Starting from the 7th century AD, the Bulgarians began their struggle to establish an independent state, with the Byzantine Empire as their main rival.
Grand Duke Boris (reigned 852-888) was the father of Simon I. During the Boris era, Bulgaria had become a major power on the Balkan Peninsula and a formidable rival of the Byzantine Empire, expanding its territory to Serbia, Croatia, and other places. But it is still a mess in terms of ideological beliefs. Boris was determined to unify the thoughts of his own people with the Greek Orthodox Church, which represented the most advanced culture of the time. He invited several disciples of the famous brothers Cyril and Methodius to seek refuge and preach in Bulgaria, but this caused dissatisfaction among some stubborn nobles in the country. Boris' determination to promote the Greek Orthodox Church never wavered. During his reign, he suppressed several rebellions of the aristocracy under the banner of restoring the old faith. Even after his abdication, he returned from the monastery and once again suppressed the rebellions of the nobles.
Simon I, the son of Boris, was sent to the Byzantine capital as a hostage from a young age. This special experience exposed him to the most advanced culture of the time from a young age, instilling in him a sense of identification with Byzantine culture and an ambition for Byzantine political status, as evidenced by his future actions.
Inheriting the throne
In 893, Simon inherited the position of Grand Duke of Bulgaria. In the second year, he provoked a war with Byzantium and won his first battle on the throne. The Byzantine Emperor Leo VI, who was overjoyed, persisted and formed an alliance with the Magyars in the north of Bulgaria, attempting to launch a pincer attack from north to south. However, he was defeated by Simon, and Leo VI had to seek peace in 897 and bow down to pay tribute to Simon.
This is the first stage of Simon's' Byzantine Offensive ', mainly aimed at competing for trade rights and spheres of influence. In 912, with the death of Leo VI, there was a dispute within Byzantium over the succession of the throne. Simon's "Byzantine Offensive" had a clearer goal - to seize the most dazzling throne in the world.

Attack on Byzantium
After the death of Leo VI, his brother Alexander seized the inheritance of his nephew Constantine, but within a year he also reported to God with his brother. Constantine VII succeeded to the throne and was regent by Archbishop Nicholas. Simon took advantage of the suspicion of the Byzantine Empire and proclaimed himself as the Roman Emperor (at that time the official name of Byzantium was still the Eastern Roman Empire), and marched towards Constantinople. Amidst the internal turmoil of Byzantium, there were two factions. One faction, led by Regent Nicholas, advocated compromise and promised that Constantine VII would marry Simon's daughter as queen, and the two countries would form an alliance in exchange for Simon's withdrawal. But the hardliners within Byzantium were very dissatisfied. They launched a palace coup, launched the regency of Empress Zoya, and withdrew their promise to Simon. Simon was furious and declared war on Byzantium once again. At his peak, Simon fully utilized his military genius and launched successful attacks, capturing Macedonia, Thessaly, Albania, and other places. In the famous Battle of the Amuro River (Battle of Anchialus) in 917, he re established the Byzantine army and penetrated deep into the Byzantine hinterland, shocking Constantinople overnight. The Byzantines once again employed their usual tactic of "using barbarians to control barbarians", instigating the Pechenegs to attack Bulgaria from the rear, leaving Simon vulnerable from both sides. This war evolved into a protracted conflict.
In 919, a coup occurred within Byzantium, and the naval commander Roman (Romanus I) sent the Empress Dowager Zoya to a monastery and subsequently married her daughter to the young emperor, proclaiming herself as the co emperor. Roman is a more resolute resistance. Simon advanced to Constantinople four times between 919-924, but Constantinople, the strongest fortress in the Middle Ages, had caused countless heroes to fail and maintained an unbreakable golden body before Simon's army. In 924, Simon and Roman signed a treaty. The following year, Simon declared himself the "Emperor of Romans and Bulgarians" on his own territory, and Roman protested on the surface, but in reality tacitly approved of the existence of this emperor. In 924, Bulgaria also conquered Serbia, which had allied with Byzantium.

Apart from war, another thing that Simon devoted his entire life to was building the new capital of Preslav, which took 28 years from the year Simon ascended the throne. This is a metropolis that combines Greek and Slavic styles. When you arrive at the outer city, you must look without knowing where you are. If you enter the city gate... you must suspect entering a dream
Simon the Great's cultural achievements made Bulgaria the center of Slavic script and culture at that time. He fostered a "Preslav School", under his guidance, scholars edited three major volumes of reading materials, the first volume being translations of works by Byzantine writers, the second volume being doctrines, and the third volume being legal codes. Simon is described in the book as a scholarly emperor who is obsessed with books, diligent like bees in seeking new works from all over the world, and recruiting talented people from all over the world to write and speak.
In the dust and dirt of the 30-year war with Byzantium, although Simon did not achieve his dream of reaching the pinnacle of Constantinople, he clearly overwhelmed this great empire militarily and dominated the entire Balkan Peninsula, becoming a world power at that time. The prosperity of the city of Preslav and the flourishing of academia also declared to the world that he was no longer a barbarian monarch. Although the First Kingdom of Bulgaria declined shortly after his death, the historical legacy he left behind will never disappear. No matter how many centuries Bulgaria has been extinct, the revival of Simon the Great's empire will always be the dream of Bulgarians. Simon the Great ranks 83rd in the "100 Emperors Who Influence the World" list.

The strength of the country during the reign of Emperor Simon the Great was not only the achievement of the Bulgarians, but also marked a milestone achievement for early Eastern European countries. Accepting the influence of advanced Byzantine culture in Eastern Orthodoxy and other aspects, but also developing its own distinctive Slavic script culture, this was the development trend in many regions of Eastern Europe thereafter. Bulgaria, which was the earliest to become strong, set an example for the emerging Eastern European nation states that were about to emerge like mushrooms after rain.