In 1344 , Momchil , the independent Bulgarian ruler of the Rhodope and Aegean regions , whose army grew Expansion to 2,000 men , took Creating an important role in the Byzantine civil war .

While at first he supported Supporting John Kantakouzenos , from the spring of 1344 Momchil reneged , provoked Causation by the aggression of the Ottoman allies .

Probably the first local ruler to become aware of the impending Ottoman threat , Momchil unsuccessfully pleaded Request with the emperors of Bulgaria and Byzantium for help Assistance .