Contra Errores Graecorum

Contra errores Graecorum, ad Urbanum IV Pontificem Maximum (Against the Errors of the Greeks, to Pope Urban IV) is a short treatise (an "opusculum") written in 1263 by Roman Catholic theologian Saint Thomas Aquinas as a contribution to Pope Urban's efforts at reunion with the Eastern Church.^[1] Aquinas wrote the treatise in 1263 while he was papal theologian and conventual lector in the Dominican studium at Orvieto after his first regency as professor of theology at the University of Paris which ended in 1259 and before he took up his duties in 1265 reforming the Dominican studium at Santa Sabina, the forerunner of the Pontifical University of Saint Thomas Aquinas, Angelicum, in Rome.

Aquinas died on his way to participate in the 1274 Second Council of Lyons, to which he had been invited, but this treatise, which he had written eleven years before and not for the use of this Council,^[2] was influential at the Council.

^ Aidan Nichols, Discovering Aquinas: An Introduction to His Life, Work, and Influence (Wm. B. Eerdmans Publishing, 2003 ISBN 0-8028-0514-0, ISBN 978-0-8028-0514-0), p. 167
^ Deno John Geanakoplos, Constantinople and the West: essays on the late Byzantine (Palaeologan) and Italian Renaissances and the Byzantine and Roman churches(Univ of Wisconsin Press, 1989 ISBN 0-299-11884-3, ISBN 978-0-299-11884-6), p. 196

[1] Aidan Nichols, Discovering Aquinas: An Introduction to His Life, Work, and Influence (Wm. B. Eerdmans Publishing, 2003 ISBN 0-8028-0514-0, ISBN 978-0-8028-0514-0), p. 167

[2] Deno John Geanakoplos, Constantinople and the West: essays on the late Byzantine (Palaeologan) and Italian Renaissances and the Byzantine and Roman churches(Univ of Wisconsin Press, 1989 ISBN 0-299-11884-3, ISBN 978-0-299-11884-6), p. 196

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