A formerly banned work: Peter Abelard's "Sic et Non" (in English, please)

Rosie Perera said:

Because he was was pronounced a heretic by the Catholic Church, this work lay in obscurity until the 19th century.

er... ah... then how was it so influential in the development of medieval logic?

"He is, arguably, the greatest logician of the Middle Ages and is equally famous as the first great nominalist philosopher. He championed the use of reason in matters of faith (he was the first to use ‘theology’ in its modern sense), and his systematic treatment of religious doctrines are as remarkable for their philosophical penetration and subtlety as they are for their audacity." (Stanford Encyclopedia of Philosophy).

Or how come we didn't know he was declared a heretic?

"More subtle and more learned than ever", as a contemporary (Otto of Freising) describes him, he took up the former quarrel with Anselm's pupils. Through their influence, his orthodoxy, especially on the doctrine of the Holy Trinity, was impeached, and he was summoned to appear before a council at Soissons, in 1121, presided over by the papal legate, Kuno, Bishop of Praneste. While it is not easy to determine exactly what took place at the Council, it is clear that there was no formal condemnation of Abelard's doctrines, but that he was nevertheless condemned to recite the Athanasian Creed, and to burn his book on the Trinity." (Catholic Encyclopedia)

Rosie Perera said:

"Abelard was condemned as a heretic and sentenced to perpetual silence (1141)

must be referring to:

"Accordingly, a council was held at Sens (the metropolitan see to which Paris was then suffragan) in 1141. On the eve of the council a meeting of bishops was held, at which Bernard was present, but not Abelard, and in that meeting a number of propositions were selected from Abelard's writings, and condemned. When, on the following morning, these propositions were read in solemn council, Abelard, informed, so it seems, of the proceedings of the evening before, refused to defend himself, declaring that he appealed to Rome. Accordingly, the propositions were condemned, but Abelard was allowed his freedom. St. Bernard now wrote to the members of the Roman Curia, with the result that Abelard had proceeded only as far as Cluny on his way to Rome when the decree of Innocent II confirming the sentence of the Council of Sens reached him. The Venerable Peter of Cluny now took up his case, obtained from Rome a mitigation of the sentence, reconciled him with St. Bernard, and gave him honourable and friendly hospitality at Cluny. There Abelard spent the last years of his life, and there at last he found the peace which he had elsewhere sought in vain. He donned the habit of the monks of Cluny and became a teacher in the school of the monastery. He died at Chalôn-sur-Saône in 1142, and was buried at the Paraclete." Catholic Encyclopedia

Rosie Perera said:

and his writings were included on the list of prohibited works (1563)."

I would expect this to be true for some of his works but I can't verify it at http://www.aloha.net/~mikesch/ILP-1559.htm although I may have simply missed it.