Byzantine–Bulgarian war of 913–927
Simeon was aware that he needed naval support to conquer Constantinople and in 922 sent envoys to the Fatimid caliph Ubayd Allah al-Mahdi Billah in Mahdia to negotiate the assistance of the powerful Arab navy.
In the first years after his accession to the throne in 893, Simeon successfully defended Bulgaria's commercial interests, acquired territory between the Black Sea and the Strandzha mountains, and imposed an annual tribute on the Byzantine Empire as a result of the Byzantine–Bulgarian war of 894–896.
[1][2] The outcome of the war confirmed Bulgarian domination in the Balkans,[3] but Simeon knew that he needed to consolidate his political, cultural and ideological base in order to fulfil his ultimate goal of claiming an imperial title for himself and eventually assuming the throne in Constantinople.
[3][5][6] Simeon continued the policy of his father Boris I (r. 852–889) of establishing and disseminating Bulgarian culture, turning the country into the literary and spiritual centre of Slavic Europe.
[9] The Magyar devastation of the country's north-eastern regions during the War of 894–896 exposed the vulnerability of Bulgaria's borders to foreign intervention under the influence of Byzantine diplomacy.
The situation further deteriorated as the emperor entered into a feud with the Ecumenical Patriarch Nicholas Mystikos over his fourth marriage, to his mistress Zoe Karbonopsina.
By securing and settling Thessalonica, the Bulgarians would have gained an important port on the Aegean Sea and would have cemented their hold on the western Balkans, creating a permanent threat to Constantinople.
The course of the negotiations is unknown – in a surviving letter to emperor Leo VI the Wise, Choirosphaktes boasted that he had "convinced" the Bulgarians not to take the city but did not mention more details.
[23] The historian John Fine argues that the provocative policy of Alexander did little to influence Simeon's decision, as he had already planned an invasion, having taken into account that on the Byzantine throne sat a man who was unpopular, inexperienced and possibly alcoholic and whose successor, Constantine VII, was a sickly little boy, considered by many to be illegitimate.
[b][22][24] While Bulgaria was preparing for war, on 6 June 913 Alexander died, leaving Constantinople in chaos with an under-aged emperor under the regency of patriarch Mystikos.
Nicholas Mystikos sent a letter which, while praising the wisdom of Simeon, accused him of attacking an "orphan child" (i.e., Constantine VII) who had done nothing to insult him, but his efforts were in vain.
The head of the Byzantine chancery, Theodore Daphnopates, wrote about the campaign fifteen years later: "There was an earthquake, felt even by those who lived beyond the Pillars of Hercules.
[29][30][31] After negotiations between Theodore Sigritsa and the regency, a feast was organised in honour of Simeon's two sons in the Palace of Blachernae presided over personally by Constantine VII.
[37][41] To deal with the Bulgarian threat for good, the Byzantines took measures to end the conflict with the Abbasid Caliphate in the east and attempted to create a wide anti-Bulgarian coalition.
[37] However, the court in Preslav was warned about the negotiations by prince Michael of Zahumlje, a loyal ally of Bulgaria, and Simeon was able to prevent an immediate Serb attack.
He did manage to convince some tribes to send aid, but eventually the Byzantine navy refused to transport them to the south of the Danube river, probably as a result of the jealousy that existed between Bogas and the ambitious admiral Romanos Lekapenos.
[64] The annexation was a necessary move since the Serbs had proven to be unreliable allies[64] and Simeon had grown wary of the inevitable pattern of war, bribery and defection.
[65] After the threat from Serbia was eliminated in 917, Simeon personally led a campaign in the Theme of Hellas and penetrated deep to the south, reaching the Isthmus of Corinth.
After receiving their report, Simeon sent five men into the city with axes to eliminate the guards, break the hinges, and open the gates for the Bulgarian army.
[68] In the autumn of 920, the Bulgarian army campaigned deep into Thrace, reaching the Dardanelles and setting up camp on the shore of the Gallipoli Peninsula just across from the city of Lampsacus in Asia Minor.
[59][61] These actions caused great concern to the Byzantine court because the Bulgarians could cut Constantinople off from the Aegean Sea if they were successful in securing Gallipoli and Lampsacus.
The Byzantines summoned a large army, including troops from the city garrison, the imperial guard, and sailors from the navy, commanded by Pothos Argyros and Admiral Alexios Mosele.
[60][81] When Romanos I learned about the secret negotiations, the Bulgarians were imprisoned, while the Arab envoys were allowed to return to Al-Mahdiyyah with rich gifts for the caliph.
An Arab expedition from the Abbasid Caliphate under Thamal al-Dulafi landed on the Aegean coast of Thrace, and the Bulgarians established contact with them and sent envoys in Tarsus.
Prior to the meeting at the suburb of Kosmidion, the Bulgarians took precautions and carefully inspected the specially prepared platform – they still remembered the failed Byzantine attempt to assassinate Khan Krum (r. 803–814) during negotiations at the same place a century earlier, in 813.
At the beginning of Peter I's reign, the most influential person in the court was his maternal uncle, George Sursuvul, who served at first as a regent of the young monarch.
[97][99] The treaty restored the border approximately along the lines agreed in 904 – the Bulgarians returned most of Simeon I's conquests in Thrace, Thessaly and Hellas and retained firm control over most of Macedonia and the larger part of Epirus.
[101] During most of his subsequent rule until 965, Peter I presided over a Golden Age of the Bulgarian state in a period of political consolidation, economic expansion and cultural activity.
[102][104] The influence of the landed nobility and the higher clergy increased significantly at the expense of the personal privileges of the peasantry, causing friction in the society.
[106] In that setting during the reign of Peter I arose Bogomilism – a dualistic heretic sect that in the subsequent decades and centuries spread to the Byzantine Empire, northern Italy and southern France (cf.
