Caius or Gaius, pope from 283 to 296, was the son of Gaius, or of Concordius, a relative of the emperor Diocletian, and became pope on the 17th of December 283. His tomb, with the original epitaph, was discovered in the cemetery of Calixtus and in it the ring with which he used to seal his letters (see Arringhi, Roma subterr., l. iv. c. xlviii. p. 426). He died in 296.