Second Bulgarian Empire

State · 1188–1394 CE · at its largest around 1236 CE

Bulgarian state restored by the Asen brothers' revolt against Byzantium in 1185, with its capital at Tarnovo; it was conquered by the Ottomans by 1396.

On its lands while it lasted

Veliko Tarnovo (c. 1188 CE): Capital of Second Bulgarian Empire (1188–1394).
Sibiu (1191 CE): Capital of Principality of Transylvania (1692–1695).
Fourth Crusade (1202–1204 CE): Crusaders transported by Venice sacked the Christian city of Zara, then diverted to Constantinople, which they stormed and plundered in April 1204, founding the Latin Empire.
Sack of Constantinople (1204) (1204 CE): Armies of the Fourth Crusade sacked Constantinople and set up a Latin Empire, permanently weakening Byzantium.
Timisoara (1266 CE): Capital of Kingdom of Hungary (1315–1323).
Stefan Dusan (c. 1308 CE – 1355 CE): Serbian ruler crowned emperor at Skopje in 1346, who expanded Serbia to its greatest extent and issued a law code.
Câmpulung (c. 1314 CE): Capital of Principality of Wallachia (1314–1858).
Prizren (c. 1352 CE): Capital of Serbian Empire (1352–1371).
Vidin (c. 1363 CE): Capital of Despotate of Vidin (1363–1396).
Janissaries (c. 1363–1826 CE): Sultan Murad I created the Janissaries around 1363 as an elite Ottoman infantry corps, later filled through the devshirme levy of Christian boys. They grew into a powerful political force until Mahmud II abolished the corps in 1826.
Kavarna (c. 1363 CE): Capital of Despotate of Dobruja (1363–1394).
Battle of Kosovo (1389 CE): A Serbian-led army under Prince Lazar fought the Ottomans under Murad I; both rulers were killed, and Serbia soon became an Ottoman vassal.