The early martyrdoms in the period down to Constantine are a conspicuously urban affair. They do not occur in the mountainous regions of Greece, or in the remote parts of central Anatolia, or in the near eastern steppe, or on the fringes of the Sahara in North Africa. For the most part, they take place in the greatest cities of the Roman world, predominantly in the eastern part of it. Apart from Justin at Rome and the group of martyrs at Lyon in France, the early martyrdoms provide a check-list of the most prosperous and important cities of the eastern Roman empire: Pergamum, Smyrna, Caesarea by the Sea, Carthage, Alexandria. In Greece, it is Thessalonica that has its martyrs, not Athens, and this is a proper reflection of the relative importance of the two places at that time. It was only in the period just before Constantine that there was a conspicuous deviation from this pattern of urban martyrdoms.

The spread of Christianity into the rank and file of the Roman army (and perhaps also the increasing importance of soldier-emperors in the third century) led to the first group of soldier-martyrs, as reflected in the martyrdom at Durostorum on the Danube.