Trade war with Byzantium and Magyar invasions With Simeon on the throne, the long-lasting peace with the Byzantine Empire established by his father was about to end. A conflict arose when
Byzantine Emperor Leo VI the Wise, allegedly acting under pressure from his mistress
Zoe Zaoutzaina and her father
Stylianos Zaoutzes, moved the marketplace for Bulgarian goods from Constantinople to
Thessaloniki, Unable to effectively respond to the Bulgarian campaign due to the engagement of their forces against the Arabs, the Byzantines convinced the Magyars to attack Bulgaria, Leo VI may have also concluded an agreement with Arnulf to make sure that the
Franks did not support Simeon against the Magyars. In addition, the talented commander
Nikephoros Phokas was called back from
southern Italy to lead a separate army against Bulgaria in 895 with the intention to merely overawe the Bulgarians. Simeon, unaware of the threat from the north, rushed to meet Phokas' forces, but the two armies did not engage in a fight. Instead, the Byzantines offered peace, informing him of both the Byzantine foot and maritime campaign, but intentionally did not notify him of the planned Magyar attack. Simeon did not trust the envoy and, after sending him to prison, ordered the Byzantine navy's route into the Danube closed off with ropes and chains, intending to hold it until he had dealt with Phokas. Despite the problems they encountered because of the fencing, the Byzantines ultimately managed to ferry the Magyar forces led by
Árpád's son Liüntika across the Danube, possibly near modern
Galaţi, and assisted them in pillaging the nearby Bulgarian lands. Once notified of the surprise invasion, Simeon headed north to stop the Magyars, leaving some of his troops at the southern border to prevent an attack by Phokas. Simeon's two encounters with the enemy in
northern Dobruja resulted in Magyar victories, After pillaging much of Bulgaria and reaching Preslav, the Magyars returned to their lands, but not before Simeon had concluded an armistice with Byzantium towards the summer of 895.
Anti-Magyar campaign and further wars with Byzantium . Having dealt with the pressure from the Magyars and the Byzantines, Simeon was free to plan a campaign against the Magyars looking for retribution. He negotiated a joint force with the Magyars' eastern neighbours, the
Pechenegs, and imprisoned the Byzantine envoy
Leo Choirosphaktes in order to delay the release of the captives until after the campaign against the Magyars. This would allow him to renegotiate the peace conditions in his favour. In an exchange of letters with the envoy, Simeon refused to release the captives and ridiculed Leo VI's
astrological abilities. Using a Magyar invasion in the lands of the neighbouring Slavs in 896 as a
casus belli, Simeon headed against the Magyars together with his Pecheneg allies, defeating them completely in the
Battle of Southern Buh and making them leave
Etelköz forever and settle in
Pannonia. He was met in
Thrace by a hastily assembled Byzantine army, but annihilated the Byzantine forces in the
Battle of Bulgarophygon (at modern
Babaeski, Turkey). Arming Arab captives and sending them to fight with the Bulgarians as a desperate measure, Leo VI managed to repel the Bulgarians from Constantinople, which they had besieged. The war ended with a peace treaty which formally lasted until around Leo VI's death in 912 Under the treaty, the Byzantines also ceded an area between the Black Sea and
Strandža to the Bulgarian Empire. Meanwhile, Simeon had also imposed his authority over
Serbia in return for recognizing
Petar Gojniković as their ruler. Simeon often violated the peace treaty with Byzantium, attacking and conquering Byzantine territory on several occasions, such as in 904, when the Bulgarian raids were used by Arabs led by the Byzantine renegade
Leo of Tripoli to undertake a maritime campaign and seize Thessaloniki. After the Arabs plundered the city, it was an easy target for Bulgaria and the nearby Slavic tribes. In order to dissuade Simeon from capturing the city and populating it with Slavs, Leo VI was forced to make further territorial concessions to the Bulgarians in the modern region of
Macedonia. With the treaty of 904, all Slavic-inhabited lands in modern southern Macedonia and southern
Albania were ceded to the Bulgarian Empire, with the border line running some 20 kilometres north of Thessaloniki.
Recognition as emperor The death of Leo VI on 11 May 912 and the accession of his infant son
Constantine VII under the guidance of Leo's brother
Alexander, who expelled Leo's wife Zoe from the palace, constituted a great opportunity for Simeon to attempt another campaign against Constantinople, the conquest of which remained the dream of his life. In early 913, Simeon's envoys, who had arrived in Constantinople to renew the peace of 896, were sent away by Alexander, who refused to pay the annual tribute, urging Simeon to
prepare for war. Before Simeon could attack, Alexander died, on 6 June 913, leaving the empire in the hands of a regency council headed by
Patriarch Nicholas Mystikos. Many residents of Constantinople did not recognize the young emperor and instead supported the pretender Constantine Doukas, which, exacerbated by revolts in southern Italy and the planned Arab invasion in eastern Anatolia, was all to Simeon's advantage. Nicholas Mystikos tried to discourage Simeon from invading Byzantium in a long series of pleading letters, but the Bulgarian ruler nevertheless attacked in full force in late July or August 913, reaching Constantinople without any serious resistance. The anarchy in Constantinople had ceased after the murder of the pretender Constantine Doukas, however, and a government had promptly been formed with Patriarch Nicholas at the head. This urged Simeon to raise his siege and enter peace negotiations, to the joy of the Byzantines. the promise that Constantine VII would marry one of Simeon's daughters, Shortly after Simeon visited Constantinople, Constantine's mother Zoe returned to the palace on the insistence of the young emperor and immediately proceeded to eliminate the regents. Through a plot, she managed to assume power in February 914, practically removing Patriarch Nicholas from the government, disowning and obscuring his recognition of Simeon's imperial title, and rejecting the planned marriage of her son to one of Simeon's daughters. Simeon had to resort to war to achieve his goals. He invaded Thrace in the summer of 914 and captured
Adrianople. Zoe was quick to send Simeon numerous presents in order to conciliate him, and she managed to convince him to cede back Adrianople and withdraw his army. In the following years, Simeon's forces were engaged in the northwestern Byzantine provinces, around Drač (
Durrës) and Thessaloniki, but did not make a move against Constantinople.
Victories at Achelous and Katasyrtai , Madrid Skylitzes. By 917, Simeon was preparing for yet another war against Byzantium. He attempted to conclude an anti-Byzantine union with the Pechenegs, but his envoys could not match the financial resources of the Byzantines, who succeeded in outbidding them. The Byzantines hatched a large-scale campaign against Bulgaria and also tried to persuade the Serbian Prince Petar Gojniković to attack the Bulgarians with Magyar support. In 917, a particularly strong Byzantine army led by
Leo Phokas the Elder, son of
Nikephoros Phokas, invaded Bulgaria accompanied by the Byzantine navy under the command of
Romanos Lekapenos, which sailed to the Bulgarian Black Sea ports. En route to Mesembria (
Nesebǎr), where they were supposed to be reinforced by troops transported by the navy, Phokas' forces stopped to rest near the river of
Achelous, not far from the port of Anchialos (
Pomorie). Once informed of the invasion, Simeon rushed to intercept the Byzantines, and attacked them from the nearby hills while they were resting disorganized. In the
Battle of Achelous of 20 August 917, one of the largest in medieval history, the Bulgarians completely routed the Byzantines and killed many of their commanders, although Phokas managed to escape to Mesembria. Decades later,
Leo the Deacon would write that "piles of bones can still be seen today at the river Achelous, where the fleeing army of the Romans was then infamously slain". The planned Pecheneg attack from the north also failed, as the Pechenegs quarrelled with
admiral Lekapenos, who refused to transport them across the Danube to aid the main Byzantine army. Simeon's army quickly followed up the victory of Achelous with another success. The Bulgarian regiments attacked and again defeated the Byzantines, destroying some of their last units before returning to Bulgaria.
Suppression of Serbian unrest and late campaigns against Byzantium Immediately after that campaign, Simeon sought to punish the Serbian ruler Petar Gojniković who had attempted to betray him by concluding an alliance with the Byzantines. Meanwhile, the Byzantine military failures forced another change of government in Constantinople: the admiral Romanos Lekapenos replaced Zoe as regent of the young Constantine VII in 919, forcing her back into a convent. Romanos betrothed his daughter
Helena Lekapene to Constantine and advanced to the rank of co-emperor in December 920, effectively assuming the government of the empire, which was largely what Simeon had planned to do. No longer able to climb to the Byzantine throne by diplomatic means, the infuriated Simeon once again had to wage war to impose his will. Between 920 and 922, Bulgaria increased its pressure on Byzantium, campaigning in the west through
Thessaly reaching the
Isthmus of Corinth and in the east in Thrace, reaching and crossing the
Dardanelles to lay siege on the town of
Lampsacus. In the meantime, the Byzantines attempted to ignite Serbia against Simeon, but he substituted Pavle with Zaharije Pribisavljević, a former refugee at Constantinople that he had captured. In Serbia, Zaharije was persuaded by the Byzantines to revolt against Simeon. Zaharije was supported by many Bulgarians exhausted from Simeon's endless campaigns against Byzantium. The Bulgarian emperor sent his troops under Sigrica and Marmais, but they were routed and the two commanders beheaded, which forced Simeon to conclude an armistice with Byzantium in order to concentrate on the suppression of the uprising. Simeon sent an army led by
Časlav Klonimirović in 924 to depose Zaharije. He was successful, as Zaharije fled to Croatia. After this victory, the Serbian nobility was invited to come to Bulgaria and bow to the new Prince. However, he did not appear at the supposed meeting and all of them were beheaded. Bulgaria annexed Serbia directly. In the summer of 924, Simeon nevertheless arrived at Constantinople and demanded to see the patriarch and the emperor. He conversed with Romanos on the Golden Horn on 9 September 924 and arranged a truce, according to which Byzantium would pay Bulgaria an annual tax, but would be ceded back some cities on the Black Sea coast. During the interview of the two monarchs, two eagles are said to have met in the skies above and then to have parted, one of them flying over Constantinople and the other heading to Thrace, as a sign of the irreconcilability of the two rulers. In his description of this meeting,
Theophanes Continuatus mentions that "the two
emperors... conversed", which may indicate renewed Byzantine recognition of Simeon's imperial claims.
War with Croatia and death Most likely after (or possibly at the time of) Patriarch Nicholas' death in 925, Simeon raised the status of the Bulgarian Orthodox Church to a patriarchate. This may be linked to Simeon's diplomatic relations with the
Papacy between 924 and 926, during which he demanded and received Pope
John X's recognition of his title as "Emperor of the Romans", truly equal to the Byzantine emperor, and possibly the confirmation of a patriarchal dignity for the head of the Bulgarian Orthodox Church. In 926, Simeon's troops under
Alogobotur invaded Croatia, at the time a Byzantine ally, but were completely defeated by the army of
King Tomislav in the
Battle of the Bosnian Highlands. In the last months of his life, Simeon prepared for another conflict with Constantinople despite Romanos' desperate pleas for peace. On 27 May 927, Simeon died of
heart failure in his palace in Preslav. Byzantine chroniclers tie his death to a legend, according to which Romanos decapitated a statue which was Simeon's inanimate double, and he died at that very hour. He was succeeded by his son
Peter I, with George Sursubul, the new emperor's maternal uncle, initially acting as a regent. As part of the peace treaty signed in October 927 and reinforced by Peter's marriage to
Maria (Eirene), Romanos' granddaughter, the existing borders were confirmed, as were the Bulgarian ruler's imperial dignity and the head of the Bulgarian Church's patriarchal status.
H.H.Howorth opined "If he had lived, or if he had been succeeded by princes of the same martial character, it is very probable that a great Slav state reaching from the Adriatic to the Black Sea, which would have been a barrier to the Turks, might have been formed south of the Danube." == Culture and religion ==