Pope and Martyr, Semi-Double. January 17 : St. Anthony , Double. January 18 : Chair of St. Peter Apostle at Rome, Greater Double, Commemoration of St. Paul Apostle, and of St. Prisca , Virgin and Martyr. January 19 : Ss. Marius, Martha, Audifax, and Abachum , Martyrs, Simple , Commemoration of St.