Bogomilism in the context of "Gnostics"

Peter I (Church Slavonic: Петръ А҃; Bulgarian: Петър I; died 30 January 970) was the emperor (tsar) of Bulgaria from 27 May 927 to 969. Facing Bogomilism and rebellions by his brothers and also by Časlav Klonimirović early on in his reign, Peter secured more success later in life; he ensured the retreat of the invading Rus by inciting Bulgaria's allies, the Pechenegs, to attack Kiev itself. Traditionally seen as a weak ruler who lost land and prestige, recent scholarship challenges this view, emphasizing the empire's affluence and internal peace. Considered a good ruler during the Middle Ages, his name was adopted by later leaders trying to restore Bulgarian independence under Byzantine rule to emphasize legitimacy and continuity.

Boril (Bulgarian: Борил) was the emperor (tsar) of Bulgaria from 1207 to 1218. He was the son of an unnamed sister of his predecessor, Kaloyan and Kaloyan's brothers, Peter II and Ivan Asen I, who had restored the independent Bulgarian state. After Kaloyan died unexpectedly in October 1207, Boril married his widow, a Cuman princess and seized the throne. His cousin, Ivan Asen, fled from Bulgaria, enabling Boril to strengthen his position. His other kinsmen, Strez and Alexius Slav, refused to acknowledge him as the lawful monarch. Strez took possession of the land between the Struma and Vardar rivers with the support of Stefan Nemanjić of Serbia. Alexius Slav secured his rule in the Rhodope Mountains with the assistance of Henry, the Latin Emperor of Constantinople.

Boril launched unsuccessful military campaigns against the Latin Empire and the Kingdom of Thessalonica during the first years of his reign. He convoked the synod of the Bulgarian Church in early 1211. At the assembly, the bishops condemned the Bogomils for heresy. After an uprising broke out against him in Vidin between 1211 and 1214, he sought the assistance of Andrew II of Hungary, who sent reinforcements to suppress the rebellion. He made peace with the Latin Empire in late 1213 or early 1214. After Henry died in 1216 and Andrew II left Hungary for a crusade, Ivan Asen returned to Bulgaria. He captured and blinded Boril in Tarnovo in 1218.

The Synod of Tarnovo was a council of the Bulgarian Church, at that time in union with Rome, held at Veliko Tarnovo in 1211. Emperor (or Tsar) Boril of Bulgaria convoked it to condemn Bogomilism. The decisions of the synod were included in a document, now known as the Book of Boril.

The Balkan slave trade was the trade in slaves from the Balkans via Venetian slave traders across the Adriatic and Aegean Seas to Italy, Spain, and the Islamic Middle East, from the 7th century during the Early Middle Ages until the mid-15th century. It was one of the routes of the Venetian slave trade.

The trade rested on the fact that the Balkans was a religious border zone, which was significant in the Middle Ages, when religion was the determining factor on who was viewed as a legitimate target of enslavement. The Balkans was pagan territory long into the Middle Ages. After it had converted to Christianity by the 11th century, it was influenced by Orthodox Christianity and Bogomilism. This influence maintained the region's status as a religious border zone to the rest of the then-Catholic Europe. The slave trade of first pagan and then Orthodox and Bogomil Christian Slavs were exported to Italy, Spain, and Portugal in Southern Europe, but the major part of the export went to the Islamic Middle East.

Bogomil (Cyrillic: Богомил) was a 10th-century Bulgarian priest who was connected with the origins of Bogomilism. Bogomil is a Theophoric name consisting of Bog (God) and mil (dear) and means "[one who is] dear to god". He was declared a heresiarch by both the Catholic and Orthodox churches.

According to Cosmas the Priest, Bogomil first began to preach his beliefs in Bulgaria during the reign of Peter I of Bulgaria (927 to 969), which indicates that Cosmas must have been writing later than 969. As with Cosmas, the life of Bogomil is shrouded in mystery and what little is known of him comes from the sermons written against him. There is some uncertainty about his relationship to Jeremiah or whether they are the same person. The statement that Jeremiah was "a son (disciple) of Bogomil" may be an interpolation. His name is mentioned in the Book of Boril.

The Book of Boril or Boril Synodic (Bulgarian: Борилов синодик) is a medieval Bulgarian book from the beginning of the 13th century.It is an important source for the history of the Bulgarian Empire.

The book was written in conjunction with the Synod of Tarnovo (1211) convoked by tsar Boril against the Bogomils in 1211. Later additions and editions were made, dated at the end of XIV c.