Saint Demetrius of Thessaloniki is a Christian martyr and one of the most revered saints in the Eastern Orthodox Church. He is believed to have lived during the late 3rd century and was known for his strong faith and dedication to spreading Christianity. His life ended when he was executed for refusing to renounce his beliefs, and he is often depicted in iconography as a soldier. His feast day is celebrated on October 26, and he is the patron saint of Thessaloniki, Greece. Many churches and monasteries are dedicated to him, and he is also recognized as a protector of soldiers and the city itself.