Persecution at Nicomedia
Nicomedia, in Bithynia in Asia Minor (modern Izmit, Turkey), was an imperial residence and a principal stage of the persecution that began in 303 under Diocletian, the campaign historians call the Great Persecution. Its opening acts included the destruction of the city's chief Christian church and the burning of the Scriptures.
The synaxarion places the death of the four dignitaries Bassos, Eusebius, Eutychius, and Basilides, together with their wives, in this setting in 303; their households followed them in confession and martyrdom.