sentences:  After the Balkan Wars and especially after the First World War up to 600,000 Bulgarians from Aegean Macedonia and 400,000 from Western Thrace fled to Bulgaria as refugees.At this time the Internal Macedonian Revolutionary Organization (IMRO) began sending armed cheti into Greek Macedonia and Thrace to assassinate officials and stir up the spirit of the oppressed population.Kalchev came from a well known IMRO Bulgarian local family, which emigrated from Greek Macedonia to Balchik, Bulgaria after the Second Balkan War.