The First Crusade was initiated, in the name of Christ by Pope Urban II, for the recovery of Romanian (Byzantine) territory (including the Holy Land) from the Turks and Arabs. Fulcher of Chartes was a participant in the Crusade and served as chaplain to Baldwin I. A History of the Expedition to Jerusalem (Gesta Francorum Iherusalem peregrinantium) provides an absorbing chronicle of the martial pilgrimage. Image links to Edward Peters edition. ISBN recommendation: 0393094235
A brief report from the papal embassy to Constantinople of the events which precipitated the Great Schism: the separation of great portions of the Eastern Church from union with the See of Rome. Image links to W. L. North translation.
Presided over by the legates of Pope Hadrian II, this council condemned Photius (Photios I of Constantinople), whom the Eastern Orthodox uphold as a great saint. Though self proclaimed the “eighth universal synod”, according to the eminent western canonist St. Ivo of Chartes: “The synod of Constantinople which was held against Photius must not be recognized. Pope John VIII wrote to the patriarch Photius (in 879): ‘We make void that synod which was held against Photius at Constantinople and we have completely blotted it out for various reasons as well as for the fact that Pope Hadrian did not sign its acts'”. I include it as an illustration of the tumultuous and vacillating relationship then existing between the Sees of Rome and Constantinople. Image above links to Tanner translation of the decrees. ISBN recommendation: 0-87840-490-2
Decrees of the Seventh Ecumenical Council (A.D. 787) which was summoned to address the issue of iconoclasm. The council declared the production and exposure of art representing Christ and the saints to be an authentic ecclesiastical tradition in harmony with the spread of the gospel. Image above links to Tanner translation. ISBN recommendation: 0-87840-490-2. For a more detailed defense of holy art, see St. John of Damascus: Apologies Against Those Who Attack the Divine Images in Appendix I.
Bede’s Ecclesiastical History of the English People (Historia ecclesiastica gentis Anglorum) is a true classic of both early English history and ecclesiastical history. It provides a chronicle of the English people beginning with the invasion by Gaius Julius Caesar (c. 55 B.C.) and continuing through to A.D. 731. Image links to Medieval Sourcebook translation. ISBN recommendation: 0-14-044565-X
Decrees of the Sixth Ecumenical Council (A.D. 680-681) which proclaimed and confirmed, against the teaching of the Monothelites, two natural volitions and two natural principles of action in Christ, His human will following and subject to His Divine Will. Image above links to Tanner translation. ISBN recommendation: 0-87840-490-2
History of the Franks written by the sixteen successor of St Martin to the See of Tours. Begins from the Jewish/Christian creation tradition and continues through to A.D. 591. Image links to Thorpe translation. ISBN recommendation: 0140442952
Decrees of the Fifth Ecumenical Council (A.D. 553), summoned by the Emperor Flavius Justinian, which condemned (as Nestorian and heretical) teachings expounded by Theodore, bishop of Mopsuestia; Theodoret; and the so called letter of Ibas to Mari the Persian. Image above links to Tanner translation. ISBN recommendation: 0-87840-490-2
Decrees of the Fourth Ecumenical Council (A.D. 451) which affirmed along with Pope St. Leo I that Jesus Christ was both fully human and fully divine: having two natures and two wills perfectly united in his one person. Image above links to Tanner translation. ISBN recommendation: 0-87840-490-2
Decrees of the Third Ecumenical Council (A.D. 431) which explained and confirmed, against the teaching of Nestorius of Constantinople, that the Marian title Theotokos (Mother of GOD) is not in contradiction to the Catholic Faith. Image above links to Tanner translation. ISBN recommendation: 0-87840-490-2