Demetrius of Sirmium

Saint Demetrius of Sirmium (around 270, Sirmium, Roman Empire–9 April, 304 Sirmium, Roman Empire) was a Roman deacon and martyr of the early 4th century.

He is often confused with the Greek saint Demetrius of Thessaloniki who lived in the same period.

Life
He was born around 270 AD in Sirmium, present-day Sremska Mitrovica, as the son of a high-ranking officer. He was a deacon to the city's bishop, Irenaeus, who entrusted with safeguarding sacred texts. He was sentenced to death, tortured, and executed (most probably by decapitation) alongside his fellow deacons Donatus and Fortunatus, close to main city's gate on Easter Sunday, 304. He is most known among the so-called martyrs of Syrmia.

Basilica
The Basilica of St. Demetrius was erected by the Roman prefect Leontius between 426 and 441 as a three-nave basilica of the Greek type at the site believed to be where Demetrius was martyred. It was destroyed during the Avar siege of the city of Sirmium in 505. St. Demetrius is also believed to have been a co-patron saint of the small Romanesque chapel near the entrance to the city's imperial palace.

Iconography
Iconographically, St. Demetrius is depicted as a deacon or lector, vested in white toga with red deacons stole. According to later Thessalonikian tradition, he is wrongly portrayed as a young legionary, vested in Roman armour.