St. Soter was raised to the Papacy after the death of At Anicetus, about 161, and martyred under Emperor Marcus Aurelius. St. Caius succeeded St. Eutychian as Pope in 283. He died April 21, 296. For his sufferings under Diocletian he was made a martyr although he died a natural death. Ancient inscriptions bear testimony to the devotion of the faithful to these Pontiffs.
(Source: Fr. Lasance, The New Roman Missal)