The legend of the meeting of the King Tiridates III of Armenia, St. Gregory the Illuminator, Roman Emperor Constantine I, and Pope Sylvester I is an integral part of Armenian–Roman history. Over the centuries, it has been enriched with various details, sanctified, and completed during the Cilician period in the «Letter of Love and Concord». This event, often the subject of doubt and extensive studies, has also been depicted in various works of art, including miniatures, wall paintings, engravings, and icon paintings.

KeywordsGregory the Illuminator Pope Sylvester I King Tiridates III Emperor Constantine I "Letter of Love and Concord" adoption of Christianity Church San Gregorio Armeno in Naples Rome Isfahan.