Symeon of Thessalonica was a Byzantine monk, theologian, and archbishop who lived from approximately 1381 to 1429. Born in Constantinople, he eventually rose to lead the church in Thessaloniki, serving as its metropolitan during a period of intense conflict. His tenure was marked by the prolonged Ottoman siege of the city, a crisis he documented in his historical writings. As a significant religious figure and philosopher, he contributed extensively to liturgical and theological literature before his death in September 1429.