Fatima Prayer
O my Jesus, forgive us our sins, save us from the fires of hell, and lead all souls to heaven, especially those most in need of thy mercy. Amen.
Source. The decade prayer reported from the apparitions at Fatima in 1917. No pre-1929 English printing has been identified: the earliest documented publications trace to Sr. Lucia's memoirs of the 1930s and 1940s. The wording below is the universal traditional formula, printed for a century with no ownership asserted.
On the wording. Said plainly because it is the point of this library: this is the formula everyone uses, and its earliest English printing has not been pinned down. "Most in need of thy mercy" is the traditional wording; "in most need of your mercy" is the modern one.