Page "Constantine Tikh of Bulgaria" Paragraph 6

After the death of Irene in 1268, Constantine sought a reconciliation with Michael VIII by marrying his niece, Maria Kantakouzene in 1269.

However, quarrels over the surrender of Maria's promised dowry, Mesembria ( Nesebăr ), soured the improved relationship.

The Bulgarian government entered into an alliance with King Charles I of Sicily who was planning a campaign against Michael VIII with the object of restoring the Latin Empire.

Michael VIII struck back, by marrying his illegitimate daughter Euphrosyne to Nogai Khan of the Golden Horde, who pillaged Bulgaria as a Byzantine ally in 1274.

Michael VIII's attempt at church union with Rome at the Second Council of Lyons in the same year exacerbated the conflict between Bulgaria and the Byzantine Empire, as the Bulgarian empress and her mother were among that part of the Byzantine aristocracy, that was most opposed to the union.