The First Martyrs of the Church of Rome were Christians martyred in the city of Rome during Nero’s persecution in 64. The event is recorded by both Tacitus and Pope Clement I, among others. They are celebrated in the Roman Catholic Church as an optional memorial on 30 June.
This feast first came into the General Roman Calendar in the 1969 calendar reforms. The intention of the feast is to give a general celebration of early Roman martyrs. Prior to the calendar reforms, there were dozens of relatively-minor Roman martyrs celebrated or commemorated in the calendar. Several of these had scant historical evidence, but did benefit from immemorial tradition.
This feast is a replacement for the many Roman martyr feasts, whose absence allowed for a less cluttered and more “dies natale” based sanctoral calendar of more major saints. It also permitted the greater celebration of ferias, partially enacting the Second Vatican Council’s call for the Proper of Time to take a greater precedence. Each of the early Roman martyrs retain their place in the Martyrology and can be celebrated in local calendars or privately unless impeded by a greater observance.
The placement of the feast is directly after the Solemnity of Sts. Peter and Paul, who are the principal patron saints of Rome. The subsequent martyrs are associated with this patronage. The feast day was formerly occupied with a Commemoration of St. Paul, and fell in the Octave of SS Peter and Paul.
[Adapted from Wikipedia]