Jungmann, Josef A., S.J. "Chapter Fourteen: The Veneration of the Martyrs."The Early Liturgy to the Time of Gregory the Great. (translated by Francis A. Brunner, C.S.S. R., Notre Dame, Indiana: University of Notre Dame Press, 1959, pp. 175-187.
The testimony of Christians to the surrounding world was always a part of Christian faith and practice. Jungmann notes that this includes bearing witness in the presence of rulers while on trian (Jungmann 1959, 175). Those who died for their faith were naturally honored, as were those "confessors" who had merely been imprisoned or tortured. The custom of an annual commemoration was not uncommon. As with the death of any prominent or beloved person, commemorations became common, as did prayers for the dead or petitions that they would intercede for various causes (Jungmann 1959, 176). Jungmann observes that, because the life and death of a martyr was a concern to the whole church, the commemoration would be more widespread and enduring than that for a family member or friend (Jungmann 1959, 177). There are recorded instances of commemorations as early as the mid second century.
By the fourth century monuments over the graves of martyrs were turned into basilicas, especially around the boundaries of Rome (Jungmann 1959, 178). Additionally, the feast days for sints began to be published as special churchly celebrations. Tertullian speaks of a celebration of a Mass, as well as a vigil (Jungmann 1959, 179). Jungmann notes that while in some cases the Mass itself was unchanged, with only Scripture readings for the martyr being appointed, in other cases the prayers would also be adjusted (Jungmann 1959, 180). Eventually, the prayers which were variable would always be adjusted to have a reference to the martyr of the day (Jungmann 1959, 182).
Jungmann lists a number of indications that the cult of the martyrs was popular. Among other signs, he finds graffiti inscribed on and around the tombs, asking for assistance. Faithful followers were also buried near the martyr (Jungmann 1959, 182). Another interesting custom was the refrigerium, a funeral meal prepared for the dead. Jungmann notes that these celebrations could easily be abused by carousing and heavy drinking (Jungmann 1959, 1830. In more reasoned situations some would prepare a meal and give it to the poor.
The cult of the martyrs also lead to the veneration of relics (Jungmann 1959, 184). Some of the relics of the martyrs took on special connotations and were used as protective amulets (Jungmann 1959, 185). The martyrs and their relics were given great consideration. Jungmann, however, sees the "strange abuses" as emerging in later centuries (Jungmann 1959, 185).
The interactions between the cult of the martyrs and the cults of the dead are complex. The tombs of martyrs and other important dead people were the focus of intense interest and devotion (Jungmann 1959, 186). Moving bodies, body parts, or other relics was often frowned upon or prohibited by law. After the fifth century, though, even Rome, once a holdout, allowed moving or dividing such relics.