The Litany of the Sacred Heart of Jesus is one of the few litanies approved for public use, being approved in 1899 by Pope Leo XIII. This litany has 33 invocations, one for each year of Christ's life on earth. Some of the invocations go back to at least the 17th century. Through its association with the Sacred Heart of Jesus, it invites us to seek His mercy and express our love for Him.