Just to help you out here, some lists of RCC Ecumenical Councils.
The following is the list of the general councils recognized by Roman Catholics (the numbering is the customary one, and the opening year is given): (1) 1 Nicaea, 325; (2) 1 Constantinople, 381; (3) Ephesus, 431; (4) Chalcedon, 451; (5) 2 Constantinople, 553; (6) 3 Constantinople, 680; (7) 2 Nicaea, 787; (
4 Constantinople, 869; (9) 1 Lateran, 1123; (10) 2 Lateran, 1139; (11) 3 Lateran, 1179; (12) 4 Lateran, 1215; (13) 1 Lyons, 1245; (14) 2 Lyons, 1274; (15) Vienne, 1311; (16) Constance, 1414; (17) Basel and Ferrara-Florence, 1431, 1438; (18) 5 Lateran, 1512; (19) Trent, 1545; (20) 1 Vatican, 1869; (21) 2 Vatican, 1962 (see separate articles on each council; e.g., Nicaea, First Council of). The Orthodox Eastern Church recognizes the first seven and counts the Trullan Synod of 692 as an ecumenical extension of the Third Council of Constantinople. The first council was the model for the rest.http://reference.allrefer.com/encyclopedia/C/council-recognized-councils.html
The RCC list of its 21 Ecumenical Councilshttp://www.newadvent.org/library/almanac_14388a.htm
VII. SECOND COUNCIL OF NICAEA
Summary: The Second Council of Nicaea was convoked by Emperor Constantine VI and his mother Irene, under Pope Adrian I, and was presided over by the legates of Pope Adrian; it regulated the veneration of holy images. Between 300 and 367 bishops assisted.
Further Reading: www.newadvent.org/cathen/11045a.htm
VIII. FOURTH COUNCIL OF CONSTANTINOPLE
Summary: The Fourth General Council of Constantinople, under Pope Adrian II and Emperor Basil numbering 102 bishops, 3 papal legates, and 4 patriarchs, consigned to the flames the Acts of an irregular council (conciliabulum) brought together by Photius against Pope Nicholas and Ignatius the legitimate Patriarch of Constantinople; it condemned Photius who had unlawfully seized the patriarchal dignity. The Photian Schism, however, triumphed in the Greek Church, and no other general council took place in the East.
Further Reading: www.newadvent.org/cathen/04310b.htm
IX. FIRST LATERAN COUNCIL
Summary: The First Lateran Council, the first held at Rome, met under Pope Callistus II. About 900 bishops and abbots assisted. It abolished the right claimed by lay princes, of investiture with ring and crosier to ecclesiastical benefices and dealt with church discipline and the recovery of the Holy Land from the infidels.
Further Reading: www.newadvent.org/cathen/09016b.htm
Eighth Ecumenical Council -- Constantinople IV
LOCATION: Constantinople ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
YEARS: A.D. 869 - 870 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
POPE: Hadrian II, 867 - 872 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
EMPEROR: Basil, 867 - 886 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
ACTION: ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š Called by Emperor Basil and ratified by Pope Hadrian II, this council condemned and deposed PHOTIUS (820 - 891), the patriarch of Constantinople and author of the Greek schism.
NOTE: ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š In 1054 the Greek schism was actually consummated by Michael Cerularius, the Patriarch of Constantinople at that time. ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š PHOTIUS attacked enforced clerical celibacy, the addition by the West of the "FILIOQUE" to the Creed, and the crowning of Charlemagne in the West. CERULARIUS (about 200 years later) closed the churches of the Latins in Constantinople, had the Blessed Sacrament cast out and trodden underfoot as invalid, and persisted in refusing to see the three delegates sent by Pope Leo IX (1049 - 1054). ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š On 16 July, 1054, they publicly placed on the altar of Saint Sophia the document containing his excommunication.
HERETIC: ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š PHOTIUS.
(The Eastern Councils end here and the Western begin.)
Ninth Ecumenical Council -- Lateran I
LOCATION: The Basilica of Saint John Lateran in Rome ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
YEAR: A.D. 1123 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
POPE: Callistus II, 1119 - 1124 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
EMPEROR: Henry V, 1106 - 1125 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š
ACTION: ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š Called and ratified by Pope Callistus II, this council confirmed the Concordat of Worms (1122) between Emperor Henry V and Pope Callistus II, which secured that all elections of Bishops and Abbots should be made freely by the proper ecclesiastical authorities (electors). ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š In Germany the emperor was to preside over these free elections and then bestow temporal power on the bishop so chosen, in return for temporal fealty. ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š Outside Germany the emperor was to have no part in any elections.
NOTE: ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š Also dealt with at this council was the subject of clerical marriages. ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š It was decided that once ordained, a priest may not marry in either Latin or Eastern Rites.
CONTROVERSY: ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€š LAY INVESTITURE.
I'm really surprised that any Orthodox would reject the 8th as an Ecumenical Council.
St Photios pray for us!