Ad multos annos (English: For many more years) is a Latin acclamation for celebrations, and also a hymn used in the rites of the Orthodox and Catholic churches.
In the Orthodox liturgy, Ad multos annos has a Byzantine equivalent of the first millennium which is an acclamation called Eis polla eti (Greek εἰς πολλὰ ἔτη): it is part of the Polychronion.
[1] In Slavic Orthodoxy, especially Ukraine and Russia, Mnogaya leta has become a traditional celebratory song, akin to Happy birthday to you.
Today the Latin phrase is also used in greetings and toasts in academic and ecclesiastical circles,[6] especially at the Pontifical North American College in Rome where it has become a refrain.
Austrian composer Joseph Balthasar Hochreither wrote the Missa ad multos annos, his oldest surviving work from 1705, on the occasion of the consecration Abbot Maximilian Pagl of Lambach Abbey in Upper Austria.