The Uprising of Ivaylo (Bulgarian: Въстанието на Ивайло) was a rebellion of the Bulgarian peasantry against the incompetent rule of Emperor Constantine Tikh and the Bulgarian nobility. The revolt was fuelled mainly by the failure of the central authorities to confront the Mongol menace in north-eastern Bulgaria. The Mongols had looted and ravaged the Bulgarian population for decades, especially in the region of Dobrudzha. The weakness of the state institutions was a result of the accelerating process of feudalisation of the Bulgarian Empire.