Hilarius is the given name of: Hilarius of Aquileia (died c. 284), saint, bishop of Aquileia, Italy. Hilarius or Hilary of Poitiers (c. 310 – c. 367), Bishop of Poitiers and Doctor of the Church. Hilary the Deacon (Latin: Hilarius Diaconus) (fl. 355), Sardinian deacon of the Roman church. Hilarius, Archbishop of Tarragona (Spain) c. 402. Hilarius or Hilary of Arles (c. 403–449), Bishop of Arles and saint. Hilarius (praefectus urbi), praefectus urbi (prefect of Rome) in 408. Pope Hilarius or Hilary (died 468), Catholic pope and saint. Hilarius (poet) (fl.
https://en.wikipedia.org/wiki/Hilarius