The independence of Bulgaria from Byzantium was restored as a result of an insurrection in in 1185; the centre of this insurrection - the city of Turnovo - remained Bulgaria's capital until the tragic year 1393, when it was conquered by the Turks. The third ruler of the new dynasty - Asen's - was Tzar Kaloyan (1196-1207).
Seeking to achieve recognition for his revived state, Kaloyan began prolonged and complicated negotiations with Pope Innocent III, whom he promised the union of the Bulgarian church with Rome, provided that the holy father should acknowledge his tzarist rank and the patriarchal dignity of the Bulgarian church. In the long run, the Pope's legate brought only a king's crown for him and a primate's title for the pastor of the Bulgarians; that, however, did not prevent Kaloyan from signing documents in his tzarist capacity and, in fact, not carrying the union into effect at all.
In the mean time, the crusaders from the West, who in 1204 conquered Constantinople by fraud, founding the so-called Latin Empire on the ruins of Byzantium, showed an increasingly immoderate appetite for seizing Bulgaria too, more than once arrogantly challenging its monarch. This led to the battle of Odrin (1205), where Kaloyan defeated the crusaders' army. The Latin Emperor Baldwin was taken prisoner and in spite of Rome's threats to initiate a crusade against Kaloyan, Baldwin remained in Turnovo until his death (there is some evidence that he was executed on account of the intrigues of the Bulgarian tzaritza whose love for him had not been reciprocated). After the Odrin battle tzar Kaloyan waged a merciless war on two fronts - against the Latins and against the Greeks, annexing newer and newer lands to his state. This is why the Byzantine chroniclers described him as the most violent enemy of the Greek race.
Kaloyan died in 1207 during the siege of Thessaloniki - killed while sleeping by a plotter - Manastre, leader of the Koumanian mercenaries in his army.