A.M.D.G. stands for
which is latin for
The Latin phrase was a favorite of St. Ignatius of Loyola, founder of the Society of Jesus.
It is used routinely by His Holiness, Pope John Paul II. In his writings, on the top left of every page he prints the letters AMDG.
The holy abbreviation has been used throughout the ages by many. For example, the music composer Johann Sebastian Bach was known to write on his finished works, either above or below his own name, the initials "AMDG."