Bulgarian Orthodox Church in the context of "Zographou monastery"

Krum's dynasty (Bulgarian: Крумова династия) was the royal and later imperial family founded by the Khan of Bulgaria Krum (r. 803–814), producing the monarchs of First Bulgarian Empire between 803 and 991. During this period Bulgaria adopted Christianity, reached its greatest territorial extent and triggered a golden age of culture and literature. Under the patronage of these monarchs Bulgaria became the birthplace of the Cyrillic alphabet; Old Bulgarian became the lingua franca of much of Eastern Europe and it came to be known as Old Church Slavonic. As a result of the victory in the Byzantine–Bulgarian war of 913–927 the Byzantine Empire recognized the imperial title of the Bulgarian rulers and the Bulgarian Orthodox Church as an independent Patriarchate.

The last representative of the dynasty, Tsar Roman (r. 977–991), was succeeded by Tsar Samuel (r. 997–1014) of the Cometopuli dynasty, upon the former's death in Byzantine captivity in 997, after spending six years in prison. Samuel had made the last member of Krum's dynasty a nominal head of state in 977, in order to avoid conflict.

Ivan Asen II, also known as John Asen II (Bulgarian: Иван Асен II, [iˈvan ɐˈsɛn ˈftɔri]; 1190s – May/June 1241), was Emperor (Tsar) of Bulgaria from 1218 to 1241. He was still a child when his father Ivan Asen I – one of the founders of the Second Bulgarian Empire – was killed in 1196. His supporters tried to secure the throne for him after his uncle, Kaloyan, was murdered in 1207, but Kaloyan's other nephew, Boril, overcame them. Ivan Asen fled from Bulgaria and settled in the Rus' principalities.

Boril could never strengthen his rule which enabled Ivan Asen to muster an army and return to Bulgaria. He captured Tarnovo and blinded Boril in 1218. Initially, he supported the full communion of the Bulgarian Church with the Papacy and concluded alliances with the neighboring Catholic powers, Hungary and the Latin Empire of Constantinople. He tried to achieve the regency for the 11-year-old Latin Emperor, Baldwin II, after 1228, but the Latin aristocrats did not support Ivan Asen. He inflicted a crushing defeat on Theodore Komnenos Doukas of the Empire of Thessalonica, in the Battle of Klokotnitsa in 1230. Theodore's empire soon collapsed and Ivan Asen conquered large territories in Macedonia, Thessaly and Thrace.

Religion in Bulgaria has been dominated by Christianity since its adoption as the state religion in 864. The dominant form of the religion is Eastern Orthodox Christianity within the fold of the Bulgarian Orthodox Church. During the Ottoman rule of the Balkans, Islam spread to the territories of Bulgaria, and it remains a significant minority today. The Catholic Church has roots in the country since the Middle Ages, and Protestantism arrived in the 19th century; both of them remain very small minorities. Today, a significant part of the Bulgarians are not religious, or believers who do not identify with any specific religion, and Bulgaria has been the cradle of some new religions, notably the Neo-Theosophical movement of Dunovism.

Simeon I the Great (Church Slavonic: цѣсар҄ь Сѷмеѡ́нъ А҃ Вели́къ; Bulgarian: цар Симеон I Велики, romanized: Simeon I Veliki [simɛˈɔn ˈpɤrvi vɛˈliki]; Greek: Συμεών Αʹ ὁ Μέγας, romanized: Sumeṓn prôtos ho Mégas) ruled over Bulgaria from 893 to 927, during the First Bulgarian Empire. Simeon's successful campaigns against the Byzantines, Magyars and Serbs led Bulgaria to its greatest territorial expansion ever, making it the most powerful state in contemporary Eastern and Southeast Europe. His reign was also a period of unmatched cultural prosperity and enlightenment later deemed the Golden Age of Bulgarian culture.

During Simeon's rule, Bulgaria spread over a territory between the Aegean, the Adriatic and the Black seas. The newly independent Bulgarian Orthodox Church became the first new patriarchate besides the Pentarchy, and Bulgarian Glagolitic and Cyrillic translations of Christian texts spread all over the Slavic world of the time. It was at the Preslav Literary School in the 890s that the Cyrillic alphabet was developed. Halfway through his reign, Simeon assumed the title of "emperor" (Tsar), having prior to that been styled "prince" (Knyaz).

Church Slavonic is the conservative Slavic liturgical language used by the Eastern Orthodox Church in Belarus, Bulgaria, North Macedonia, Montenegro, Poland, Russia, Ukraine, Serbia, the Czech Republic and Slovakia, Slovenia and Croatia. The language appears also in the services of the Russian Orthodox Church Outside of Russia, the American Carpatho-Russian Orthodox Diocese, and occasionally in the services of the Orthodox Church in America.

In addition, Church Slavonic is used by some churches which consider themselves Orthodox but are not in communion with the Orthodox Church, such as the Montenegrin Orthodox Church and the Russian True Orthodox Church. The Russian Old Believers and the Co-Believers also use Church Slavonic.

The Patriarch of All Bulgaria (Bulgarian: Патриарх Български) is the patriarch of the Bulgarian Orthodox Church. The patriarch is officially styled as Patriarch of All Bulgaria and Metropolitan of Sofia. The current patriarch Daniil acceded to this position on 30 June 2024.

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.

In the year before the First Council of Constantinople in 381, Nicene Christianity became the official religion of the Roman Empire when Theodosius I, emperor of the East, Gratian, emperor of the West, and Gratian's junior co-ruler Valentinian II issued the Edict of Thessalonica in 380, which recognized the catholic orthodoxy, as defined by the Council of Nicea, as the Roman Empire's state religion. Historians refer to this state-sponsored church using a variety of terms: the catholic church, the orthodox church, the imperial church, the Roman church, or the Byzantine church, with some also used for wider communions extending beyond the Roman Empire. The Eastern Orthodox Church, Oriental Orthodoxy, and the Catholic Church all claim to stand in continuity from the Nicene Christian church to which Theodosius granted recognition. Political differences between the Eastern Roman Empire and the Persian Sassanid Empire led to the separation of the Church of the East in 424. A doctrinal split within the imperial church led to the independence of early Oriental Orthodoxy, while the fall of the Western Roman Empire initiated the gradual separation between Eastern and Western Christianity, culminating in the East-West schism of 1054. The Western Church evolved into the Latin Catholic Church while the Eastern Church that remained under the patronage of the Eastern empire and evolved into the Greek Orthodox Church.

Earlier in the 4th century, following the Diocletianic Persecution of 303–313 and the Donatist controversy that arose in consequence, Constantine the Great had convened councils of bishops to define the orthodoxy of the Christian faith and to expand on earlier Christian councils. A series of ecumenical councils convened by successive Roman emperors met during the 4th and the 5th centuries, but Christianity continued to suffer rifts and schisms surrounding the theological and christological doctrines of Arianism, Nestorianism, Miaphysitism, and Dyophysitism. In the 5th century, the Western Roman Empire decayed as a polity; invaders sacked Rome in 410 and in 455, and Odoacer, an Arian barbarian warlord, forced Romulus Augustus, the last nominal Western Emperor, to abdicate in 476. However, apart from the aforementioned schisms, the church as an institution persisted in communion, if not without tension, between the East and West. In the 6th century, the Byzantine armies of the Byzantine Emperor Justinian I recovered Italy and other regions of the Western Mediterranean shore. The Byzantine Empire soon lost most of these gains, but it held Rome, as part of the Exarchate of Ravenna, until 751, a period known in church history as the Byzantine Papacy. The early Muslim conquests of the 7th–9th centuries would begin a process of converting most of the then-Christian world in the Levant, Middle East, North Africa, regions of Southern Italy and the Iberian Peninsula to Islam, severely restricting the reach both of the Byzantine Empire and of its church. Christian missionary activity directed from the capital of Constantinople did not lead to a lasting expansion of the formal link between the church and the Byzantine emperor, since areas outside the Byzantine Empire's political and military control set up their own distinct churches, as in the case of Bulgaria in 919.

Sacrilege is the violation or injurious treatment of a sacred object, site or person. This can take the form of irreverence to sacred persons, places, and things. When the sacrilegious offence is verbal, it is called blasphemy, and when physical, it is often called desecration. In a more general sense, any transgression against what is seen as the virtue of religion would be a sacrilege, and so is coming near a sacred site without permission.

Most ancient religions have a concept analogous to sacrilege, often considered as a type of taboo. The basic idea is that realm of sacrum or haram stands above the world of the profane and its instantiations, see the Sacred–profane dichotomy.

Vladika or Wladika (Serbian: владика, Russian: влады́ка) is an informal Slavic title and address for bishops in the Eastern Orthodox Church and Eastern Catholic Churches, specifically the Russian, Serbian, Bulgarian, and American Orthodox Churches. In Old Church Slavonic, the meaning of the word is equivalent to English mister or lord.

From the early 16th to mid-19th century in Montenegro, the title referred to the bishop of Cetinje, who also served as the prince-bishop or leader of the Prince-Bishopric of Montenegro.

Eastern Orthodoxy in Croatia refers to adherents, religious communities, institutions and organizations of Eastern Orthodox Christianity in Croatia. It is the second-largest religious denomination in Croatia, behind the Roman Catholic Church. Over 128 000 people, forming 3.32% of the total Croatian population, are Eastern Orthodox Christians (2021).

Eastern Orthodoxy in Croatia is represented foremost by the Serbian Orthodox Church, which claims most of the Eastern Orthodox Christian faithful. Other major jurisdictions are the Bulgarian Orthodox and Macedonian Orthodox Churches. These three churches are recognized by the state. In Croatia there are also adherents to the Montenegrin Orthodox Church. In the past, there was a Croatian Orthodox Church, although it was unrecognized by the Serbian Orthodox Church.

Boris I (also Bogoris), venerated as Saint Boris I (Mihail) the Baptizer (Church Slavonic: Борисъ / Борисъ-Михаилъ, Bulgarian: Борис I / Борис-Михаил; died 2 May 907), was the ruler (knyaz) of the First Bulgarian Empire from 852 to 889. Despite a number of military setbacks, the reign of Boris I was marked with significant events that shaped Bulgarian and European history. With the Christianization of Bulgaria in 864, paganism was abolished. A skillful diplomat, Boris I successfully exploited the conflict between the Patriarchate of Constantinople and the Papacy to secure an autocephalous Bulgarian Church, thus dealing with the nobility's concerns about Byzantine interference in Bulgaria's internal affairs.

When in 885 the disciples of Saints Cyril and Methodius were banished from Great Moravia, Boris I gave them refuge and provided assistance which saved the Glagolithic and later promoted the development of the Cyrillic script in Preslav and the Slavic literature. After he abdicated in 889, his eldest son and successor tried to restore the old pagan religion but was deposed by Boris I. During the Council of Preslav which followed that event, the Byzantine clergy was replaced with Bulgarian, and the Greek language was replaced with what is now known as Old Church Slavonic.

The siege of Constantinople was fought in June 922 at the outskirts of the capital of the Byzantine Empire, Constantinople, between the forces of the First Bulgarian Empire and the Byzantines during the Byzantine–Bulgarian war of 913–927. In the summer the Byzantine Emperor Romanos I Lekapenos sent troops under the commander Saktikios to repel another Bulgarian raid at the outskirts of the Byzantine capital. The Byzantines stormed the Bulgarian camp but were defeated when they confronted the main Bulgarian forces. During his flight from the battlefield Saktikios was mortally wounded and died the following night.

The Bulgarians, who by 922 were in control of most of the Balkans, continued to ravage the Byzantine countryside virtually unopposed. However, they lacked the maritime power to conduct a successful siege of Constantinople. The subsequent attempts to negotiate a Bulgarian–Arab alliance for a joint assault of Constantinople were discovered by the Byzantines and successfully countered. The strategic situation in the Balkans remained unchanged until both sides signed a peace treaty in 927, which recognized the imperial title of the Bulgarian monarchs and the complete independence of the Bulgarian Orthodox Church as an autocephalous Patriarchate.

Patriarch Daniil or Daniel (Bulgarian: Патриарх Даниил; secular name: Atanas Trendafilov Nikolov; Bulgarian: Атанас Трендафилов Николов; born 2 March 1972) is a prelate of the Bulgarian Orthodox Church, currently serving as Patriarch of All Bulgaria since June 2024. Prior to his election, he was the Metropolitan Bishop of Vidin (2018–2024) and bishop of Dragovitia (2008–2018).

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.