Here's one "very unpapist" "Orthodox" author with the same text:
The plan for union with Byzantium was foiled; but Byzantine influence continued to increase.46 Moreover, it spread outwards from the court into the episcopate. Thus Gerbert of Aurillac, who became the first French pope in 999, took the name Sylvester II, reviving memories, in those brought up on the forged Donation, of the symphonic relationship between St. Constantine and Pope Sylvester I.47
The new Pope, breaking sharply with recent tradition, emphasised that while the Renovatio embraced Empire and Church, it had to be led by the Emperor.48 Again, it was Sylvester who, in 1001, inspired Otto to issue an act demonstrating that the Donation of Constantine was a forgery.49 Another striking characteristic of this very unpapist Pope was his declaration that there could be no question of the Pope being above the judgment of his fellow-bishops. Thus he wrote in 997: "The judgment of God is higher than that of Rome... When Pope Marcellinus offered incense to Jupiter [in 303], did all the other bishops have to do likewise? If the bishop of Rome himself sins against his brother or refuses to heed the repeated warnings of the Church, he, the bishop of Rome himself, must according to the commandments of God be treated as a pagan and a publican; for the greater the dignity, the greater the fall. If he declares us unworthy of his communion because none of us will join him against the Gospel, he will not be able to separate us from the communion of Christ."50
50. Pope Sylvester, Letter 192, quoted in Fr. Andrew Phllips, "The Three Temptations of Christ and the Mystical Sense of English History", Orthodox England, vol.. I, number 2, December, 1997, p. 6.
http://www.oodegr.com/english/istorika/britain/Fall_of_Orthodox_England.htmThe letters of Pope Sylvester II can be found there:
docuмentacatholicaomnia.eu, Sylvester II, lettersLetter 192 is on column 255, is very short, and doesn't even mention Pope Marcellinus. (see attachment)