St. Demetrius lived in the 3rd century in the city of Thessalonica, the city where the Slavic and Greek civilizations met, from where the great Slavic enlighteners Cyril and Methodius came.
Demetrius' father was the emperor's high official. His parents were secret Christians. As a baby he was baptized in a home church and was brought up in the Christian spirit.
According to one of the theories, Demetrius' parents were of the Slavic descent.
When the emperor and his army entered Thessalonica, Demetrius confessed his faith in front of him and condemned polytheism. The emperor ordered to imprison the protoconsul. Demetrius was pierced with spears in 306.
As for the cult of St. Demetrius in the Ukrainian land, Fr. Andrii Trukh in the book "Life of Saints" writes: "In Rus-Ukraine, the holy Martyr Demetrius enjoyed great veneration. It was caused by the siege of Constantinopol by our Prince Oleh. Nestor the Chronicler mentions that when the Rus army broke the Greek forces, 'the Greeks were afraid and said: let St. Demetrius be sent upon you from God.'
Later, when the Christian faith spread among our people, the princes, the army, and all the faithful gave themselves up to the guardianship of St. Demetrius.
In 1057, Prince Iziaslav (Christian name Demetrius) Yaroslavych founded in Kyiv a monastery in honor of St. Demetrius known as the Golden Domed Monastery of St. Michael.
In 1197, Prince Vsevolod (Dymytrii) Yuriiovych received as a gift from Thessalonica a part of the coffin and a shirt of St. Demetrius.
The coffin shed holy ointment which healed the sick. The prince built in Volodymyr a magnificent church, where he placed the relics.
In general, many churches were built in Ukraine in honor of St. Demetrius and many icons of him are found there.