Saint Theophilus was a deacon who endured martyrdom during the persecution against Christians under the emperors Diocletian (284-305) and Maximian (305-311). The persecution became particularly intense after a fire at the imperial court at Nicomedia. The pagans accused the Christians of setting the fire and reacted against them with terrible ferocity.
St Anthimus, who was Bishop of Nicomedia, took refuge in a neighboring village during the persecution, and encouraged his flock through letters. One of his letters, sent with Deacon Theophilus, was intercepted and given to the emperor Maximian. Theophilus was interrogated and died under torture, without revealing the whereabouts of Bishop Anthimus.