Triple: List of encyclicals of Pope Benedict XV; TITLE_(LATIN) Ad Beatissimi Apostolorum; Ad Beatissimi Apostolorum TITLE_(ENGLISH_TRANSLATION) To the Chair of the Prince of the Apostles; Ad Beatissimi Apostolorum NUMBER 1.

What is a sentence that describes this triple?
Ad Beatissimi Apostolorum, or To the Chair of the Prince of the Apostles, is Pope Benedict XV's first encyclical.