Donation of Constantine[dō-nāˈshən]
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A document fabricated probably during the 8th century, in which the emperor Constantine I purportedly grants to the Papacy temporal dominion over Italy and other western regions. Used throughout much of the Middle Ages as evidence in justifying Papal claims in secular affairs, it was demonstrated to be false in the 15th century.