Arrest and Confession
According to the synaxarion account, Anastasius was in Thessalonica with his teacher, who intended to sell Turkish clothing. He was directed to disguise himself as a Turkish merchant so that the goods could be moved without paying customs duty. When Ottoman authorities questioned him, he could not recite the Islamic prayer (kalima) and was brought before a commander who pressed him to embrace Islam.
Anastasius acknowledged his civil offense — disguising himself to evade taxes — but firmly refused to abandon his Orthodox faith. The case was referred to the mufti, who instructed the tax-collector that he held both the sword and the law and might use whichever he wished. Five Turkish witnesses were then produced to testify that the youth had blasphemed Islam. Anastasius clarified that he had disrespected Muslim customs rather than blasphemed Mohammed.