The “proto-martyrs” of Rome were the first Christians persecuted en masse by the Emperor Nero in the year 64, before Sts. Peter and Paul were martyred.
Nero was widely believed to have caused the fire that burned down much of Rome that year. He blamed the fire on the Christians, and put them to death. Many were crucified, or fed to wild animals in his circus, or tied to posts and lit up as human torches.
Today, the site of Nero’s Circus, also the spot where St. Peter’s martyrdom, is marked by the Piazza dei Protomartiri Romani (Square of the Roman Protomartyrs) in the Vatican next to St. Peter's basilica.
The martyrs were called the “disciples of the apostles.” Their faith in the face of their gruesome deaths was a powerful witness, and led to many conversions in the early Church.