The Battle of Plovdiv

After Tsar Kaloyan was killed in a coup, Boril was proclaimed tsar. He began persecuting descendants of the Asen dynasty, some of whom escaped abroad, while attempting to consolidate the country. Once he judged the domestic situation sufficiently stable, he resumed operations against the Latin Empire. His troops entered Thrace, won a battle near Boruy and advanced towards Plovdiv.

On 1 August 1208, he encountered a Latin army. Boril attempted to use Kaloyan's tactics from the Battle of Adrianople, but the knights did not fall for the same stratagem a second time and maintained their formation. Emperor Henry sent knights to attack the tsar's personal contingent.

The battle was fierce, but the knights gained the advantage and began pressing the Bulgarians. Boril escaped the attack on his own positions and withdrew his army into St Nicholas Pass.