At Perperikon, a personal seal of Empress Irina Comnena was discovered, providing evidence of correspondence between Bulgaria and Byzantium.

A significant discovery was made at Perperikon, where a personal seal of Empress Irina Comnena was found, according to Prof. Nikolay Ovcharov, head of the excavation works.

This seal, dating from the 13th century, is the fifth known worldwide and belongs to a woman of great influence in Byzantine history, the mother-in-law of Tsar Ivan Asen II. Irina Comnena was married to John III Ducas Vatatzes and came from an imperial family. The seal suggests an intense correspondence between Bulgaria and Byzantium during the period 1233-1235, in the context of the recognition of the Bulgarian Patriarchate. Ovcharov emphasized the importance of this correspondence, considering the historical events of that time, including the victory of Ivan Asen II at Klokotnitsa.

The seal depicts Irina wearing a crown and imperial garments, and on the reverse, Christ the Savior is represented, a rare iconography. This is the fourth discovery of this type at Perperikon, alongside other seals of Byzantine rulers.