When Basil II conquered Bulgaria in 1018, he inaugurated over 100 years of Byzantine rule in Bulgaria. But under Basil’s successors the fortunes of the Byzantine Empire began to fall. Although Byzantium briefly recovered under the first three emperors from the Komnenos Dynasty (1081-1180), after 1180 came a string of mostly incompetent emperors. Bulgaria took advantage of a weakened Byzantium, reasserting its independence and then taking advantage of the fractured Balkans region following the sacking of Constantinople during the Fourth Crusade.
Independent Once Again
Fed up with the demands of the new Byzantine emperor, Isaac II Angelos (r. 1185-1195), two brothers, Theodore and Asen, led a rebellion against Byzantine rule. Theodore declared himself Peter II of Bulgaria (r. 1185-1197) and gathered popular support. He also gained the support of the nomadic Cumans to the north. Their rebellion largely succeeded due to the incompetence of Isaac and other pressing issues affecting the Byzantine Empire. Isaac removed one of his better generals from leading the Byzantine army against the Bulgarian rebels because he was worried about him rebelling. The rebels overwhelmed the blind general that Isaac replaced him with. The next general that Isaac sent actually ended up rebelling, but was killed quickly. In the meantime, Byzantine forces were also trying to eject the Normans from the western part of the Balkans.
By taking advantage of these problems in Byzantium, Peter and Asen (who had been crowned Ivan Asen I in 1187 or 1188) successfully established Bulgarian independence. Isaac launched several more campaigns, but the Byzantine army was decisively defeated at the Battle of Arcadiopolis in 1194 and Isaac’s attempted anti-Bulgarian alliance with Hungary failed since Isaac was blinded and deposed by his brother, Alexios III (r. 1195-1203).
Bulgaria could have faced a major crisis when Asen was murdered in 1196 and Peter was murdered the next year. But the Byzantine Empire had become even weaker under the corrupt and incompetent Alexios III. Bulgaria also gained a strong ruler in Kaloyan (r. 1196-1207), Peter and Asen’s younger brother. Under his rule Bulgaria expanded its borders. He also received a crown from the Pope in exchange for accepting papal primacy.
In 1204, the Fourth Crusade sacked Constantinople, effectively destroying the Byzantine Empire, at least until 1261 when the Empire of Nicaea retook Constantinople. The Byzantine Empire fractured: several Latin crusader states emerged in Greece and Thrace while three Greek Byzantine successor states also emerged. The Latin Empire was set up at Constantinople, but from the start it was weak. Kaloyan invaded the weak empire and captured its emperor, Baldwin, at the Battle of Adrianople in 1205. He was leading an assault on Thessalonica when he mysteriously died in 1207.
Although Bulgaria faced several military defeats and setbacks under Kaloyan’s successor, Boril (r. 1207-1218), Ivan Asen II (r. 1218-1241)turned Bulgaria’s fortunes around yet again. Ivan Asen destroyed the army of the Despotate of Epiros in 1230 at the Battle of Klokotnitsa, captured its ruler, and conquered Epirote territories. For the rest of his reign, Ivan Asen played off various local powers such as the Empire of Nicaea, the Latin Empire, and the Despotate of Epiros against each other, further enhancing its power. In fact, Bulgaria scored one of the few victories against the invading Mongol hordes in 1241.
Under its crafty rulers, Bulgaria had regained its independence and emerged as a major player in Balkan politics. However, during the following decades Bulgaria would experience a sharp decline, partially due to having less capable rulers and partially because Bulgaria could no longer successfully take advantage of its neighbors and their weaknesses. Nonetheless, the Second Bulgaria Empire persisted for over two centuries, passing down to later day Bulgarians a potent memory of medieval greatness that persisted through centuries of Ottoman rule.