Focuses on the Syriac poem which was devoted to a parrot able to sing the Trishagion according to the addition of Peter the Fuller. Existing studies of the Addition to the Trishagion; Analysis of the content and structure of the poem; Isaac of Antioch or of Edessa as a very precious piece of evidence as to how Peter the Fuller was able to provoke riots in more than one region where he innovated in the liturgical field.