Petros Bereketis (Greek: Πέτρος Μπερεκέτης) or Peter the Sweet (Πέτρος ο Γλυκής) was one of the most innovative musicians of 17th-century Constantinople (Ottoman period). He, together with Panagiotes the New Chrysaphes, Balasios the Priest and Germanos Bishop of New Patras was one of the most influential figures in the evolution of the Byzantine psaltic art following the fall of Constantinople in 1453, although he never was associated with the Patriarchate in Fener. For many years, he served as the protopsaltis (first cantor) of the parochial church St. Constantine of the Hypsomatheia (Samatya) quarter close to the Marmara coast.
During his lifetime, which is approximately supposed to be between 1665 and 1725, while Chrysanthos mentioned that he served there in the time of the Archon Protopsaltis at the Great Church of Christ of Panagiotis Halatzoglou and his Lampadarios John Trapezountios (1727–1748).