Nereus and Achilleus were Praetorian soldiers who converted to Christianity in the second century. The persecution of Diocletian aimed at eliminating Christianity first from the Roman Army. In 304 they died courageously for Christ. One tradition suggests they were baptised by St Peter himself and eventually beheaded while in exile at Terracina. An ancient basilica in Rome is dedicated to their memory. – CTS New Daily Roman Missal 2012, p 2679; Vatican II Weekday Missal 1975, p 1665.
Pancras or Pancratius was, according to legend, only fourteen years old when he was martyred during the reign of Diocletian, perhaps on the same day and year (304) as Nereus and Achilleus. He was buried on the Via Aurelia and a basilica erected over his tomb. His cult spread quickly. Ancient churches were dedicated to him in Canterbury and London. Similar to Agnes, he has been across the centuries an inspiration to youthful followers of Christ. – CTS New Daily Roman Missal 2012, p 2681; Vatican II Weekday Missal 1975, p 1665.