Kaloyan of Bulgaria in the context of "Ivan Asen II"

The Second Bulgarian Empire (Middle Bulgarian: Ц(а)рьство бл(ъ)гарское; Modern Bulgarian: Второ българско царство, romanized: Vtoro Balgarsko Tsarstvo) was a medieval Bulgarian state that existed between 1185 and 1422. A successor to the First Bulgarian Empire, it reached the peak of its power under Tsars Kaloyan and Ivan Asen II before gradually being conquered by the Ottomans in the late 14th century.

Until 1256, the Second Bulgarian Empire was the dominant power in the Balkans, defeating the Byzantine Empire in several major battles. In 1205, Emperor Kaloyan defeated the newly established Latin Empire in the Battle of Adrianople. His nephew Ivan Asen II defeated the Despotate of Epiros and made Bulgaria a regional power again. During his reign, Bulgaria spread from the Adriatic to the Black Sea and the economy flourished. In the late 13th century, however, the Empire declined under constant invasions by Mongols, Byzantines, Hungarians, and Serbs, as well as internal unrest and revolts. The 14th century saw a temporary recovery and stability, but also the peak of Balkan feudalism as central authorities gradually lost power in many regions. Bulgaria was divided into three parts on the eve of the Ottoman invasion.

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.

Peter II, born Theodor, also known as Theodor-Peter (Bulgarian: Теодор-Петър; died in 1197), was the first emperor or tsar of the restored Bulgarian Empire from 1185 to 1197. He hails from the Byzantine theme of Paristrion, although his exact place and date of birth are unknown.

He and his younger brothers, Asen and Kaloyan, were mentioned as Vlachs in most foreign contemporaneous sources but they were probably of a mixed Vlach, Bulgarian, and Cuman origin. In 1185, Theodor and Asen approached the Byzantine Emperor Isaac II Angelos in Thrace, demanding an estate in the Balkan Mountains. After the Emperor refused and humiliated them, they decided to incite a rebellion, taking advantage of the discontent that a new tax had caused among the Bulgarians and Vlachs. To convince their compatriots to join them, they had native prophets declare that Saint Demetrius of Thessalonica had abandoned the Romans in favour of the Bulgarians and Vlachs. Before the end of the year, Theodor was crowned Emperor of Bulgaria, taking the name Peter and adopting the insignia used only by emperors.

Ivan Asen I, also known as Asen I or John Asen I (Bulgarian: Иван Асен I; died in 1196), was emperor or tsar of Bulgaria from 1187/1188 to 1196 as co-ruler with his elder brother, Peter II. Hailing from the Byzantine theme of Paristrion, his exact place and date of birth are unknown. Most contemporaneous chronicles describe Asen and his brothers, Theodor (Peter) and Kaloyan, as Vlachs but they were probably of mixed Bulgarian, Cuman and Vlach ancestry.

In 1185, Asen and Theodor went to see the Byzantine Emperor Isaac II Angelos in Thrace to demand an estate in the Balkan Mountains. After the Emperor refused and humiliated them, the brothers persuaded their Bulgarian and Vlach compatriots to rise up against the Byzantine Empire. Before the end of the year, Theodor was crowned Emperor of Bulgaria, taking the name Peter. After Isaac II defeated them in early 1186, Asen and Peter fled north over the Danube but returned in the autumn, accompanied by Cuman reinforcements. They captured Paristrion and began pillaging the nearby Byzantine territories.

The Battle of Adrianople occurred around Adrianople on April 14, 1205, between Bulgarians, Cumans and Vlachs under the command of Tsar Kaloyan of Bulgaria, and Crusaders under Baldwin I, who only months before had been crowned Emperor of Constantinople, allied with Venetians under Doge Enrico Dandolo. The battle was won by the Bulgarian Empire after a successful ambush.

A titular see in various churches is an episcopal see of a former diocese that no longer functions, sometimes called a "dead diocese". The ordinary or hierarch of such a see may be styled a "titular metropolitan" (highest rank), "titular archbishop" (intermediary rank) or "titular bishop" (lowest rank), which normally goes by the status conferred on the titular see.

Titular sees are dioceses that no longer functionally exist, often because the territory was conquered by Muslims or because it is schismatic. The Greek–Turkish population exchange of 1923 also contributed to titular sees. The see of Maximianoupolis along with the town that shared its name was destroyed by the Bulgarians under Emperor Kaloyan in 1207; the town and the see were under the control of the Latin Empire, which took Constantinople during the Fourth Crusade in 1204. Parthenia, in north Africa, was abandoned and swallowed by desert sand.

Baldwin I (Dutch: Boudewijn; French: Baudouin; July 1172 – c. 1205) was the first Emperor of the Latin Empire of Constantinople; Count of Flanders (as Baldwin IX) from 1194 to 1205 and Count of Hainaut (as Baldwin VI) from 1195 to 1205. Baldwin was one of the most prominent leaders of the Fourth Crusade, which resulted in the sack of Constantinople in 1204, the conquest of large parts of the Byzantine Empire, and the foundation of the Latin Empire. The following year he was defeated at the Battle of Adrianople by Kaloyan, the emperor of Bulgaria, and spent his last days as a prisoner.

The struggle for Constantinople was a complex series of conflicts following the dissolution of the Byzantine Empire in the aftermath of the Fourth Crusade in 1204, fought between the Latin Empire established by the Crusaders, various Byzantine successor states, and foreign powers such as the Second Bulgarian Empire and Sultanate of Rum, for control of Constantinople and supremacy within the former imperial territories.

At the time of the Fourth Crusade, the Byzantine Empire was already divided by internal revolts. In the aftermath of the Crusader sack of Constantinople, the empire was dissolved into a patchwork of territories held by various pretenders and warlords. The former Byzantine emperors Alexios III and Alexios V both aspired to retake the capital, though were defeated by the Latins. The early years after 1204 saw the rise and fall of numerous Byzantine statelets; the Latins managed to defeat warlords such as Leo Sgouros but were unable to halt the formation of the more well-organized rump states of the Empire of Nicaea, Empire of Trebizond, and Despotate of Epirus. The prospect of a potential swift Latin conquest of the entire former empire's territories effectively ended when the Bulgarian ruler Kaloyan defeated the Latin army at the Battle of Adrianople (1205).