d worship, but also of temporal dominion over Rome,
Italy and "the provinces, places and _civitates_ of the western
regions." The famous document, known as the _Constitutum Constantini_
and compounded of various elements (notably the apocryphal _Vita S.
Silvestri_), was forged at Rome some time between the middle and end of
the 8th century, was included in the 9th century in the collection known
as the False Decretals, two centuries later was incorporated in the
_Decretum_ by a pupil of Gratian, and in Gibbon's day was still
"enrolled among the decrees of the canon law," though already rejected
"by the tacit or modest censure of the advocates of the Roman church."
It is now universally admitted to be a gross forgery.[1] In spite,
however, of Gibbon's characteristic scepticism on this point, it is
certain that the _Constitutum_ was regarded as genuine both by the
friends and the enemies of the papal pretensions throughout the middle
ages.[2] Though no use of it was made by the popes during the 9th and
10th centuries, it was quoted as authoritative by eminent ecclesiastics
of the Frankish empire (e.g. by Ado of Vienne and Hincmar of Reims), and
it was employed by two Frankish popes, Gregory V. and Silvester II., in
urging certain territorial claims. But not till 1050 was it made the
basis of the larger papal claims, when another Frankish pope, Leo IX.,
used it in his controversy with the Byzantines. From this time forward
it was increasingly used by popes and canonists in support of the papal
pretensions, and from the 12th century onwards became a powerful weapon
of the spiritual against the temporal powers. It is, however, as
Cardinal Hergenrother points out, possible to exaggerate its importance
in this respect; a charter purporting to be a grant by an emperor to a
pope of spiritual as well as temporal jurisdiction was at best a
double-edged weapon; and the popes generally preferred to base their
claim to universal sovereignty on their direct commission as vicars of
God. By the partisans of the Empire, on the other hand, the Donation was
looked upon as the _fons et origo malorum_, and Constantine was regarded
as having, in his new-born zeal, betrayed his imperial trust. The
expression of this opinion is not uncommon in medieval literature (e.g.
Walther von der Vogelweide, Pfeiffer's edition, 1880, Nos. 85 and 164),
the most famous instance being in the _Inferno_ of Dante (xix. 115):

"Ahi, Costantin, di questo mal fu m