Not really. Beofre Vatican II, they have been using Greek in their liturgy, used leavened bread for Mass, made much use of incense, allowed their clergy to be married and considered pride the worst sin of all. The Catholic Church never had these even before Vatican II.
No the Eastern rites have always been different than that of the Western rites however they both believe in the true presence of Jesus in the Eucharist. EWTN television sometimes airs the different masses of all the Catholic Churches.
Orthodoxy is more like Catholicism without the Supremacy and Infallibility of the Pope.
Orthodoxy only recognizes the first 7 Ecumenical Councils.
Orthodoxy does not hold with the foliage's addition to the Nicene Creed.
Imagine Catholicism without a single Papal Edict and with all matters of doctrine being decided by the Council of Cardinals.
Now imagine no higher office within the Church than the Cardinals and you have a fairly good idea.
After all...
before 1054 the pope was just another Patriarch of the Orthodox Church.
The biggest difference you will probably find is married priests. As long as he gets married before he is ordained, a priest is allowed to get married. If he is single when he is ordained, a priest is expected to remain celibate. If he becomes a widower, a priest is not allowed to remarry. A priest's wife is called a "presbytery."
BTW: The Eastern Orthodox Church is not the same thing as The Eastern Rite Catholic Church.
As for languages, the "Roman Orthodox Church" (beef. 1054) did the Liturgy in Latin, The Greek Orthodox Church did/does it in Greek, Russian Orthodox - Russian, Serbian Orthodox - Serbian, Antiochian Orthodox - Arabic, OCA (Orthodox Church of America) - English well... you get the idea.
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Eastern Orthodox Church has always allowed native languages in the services. EOC also does not support Roman post-schism ad dons (like papal supremacy). The only one thing EOC and Roman Church before VII have in common is the respect for the Liturgy.
Vatican II did not modify but rather clarified and made explicit what may have been uncertain or unclear in the field of ecumenical relations. ?The Second Vatican Council neither changed nor intended to change? Catholic doctrine on the church, it said, ?rather it developed, deepened and more fully explained it.
There was only the Catholic Church which was composed of the Eastern/Asian branches and the Western Church until 1054 AD . So being first is not a point as the Church first began in Jerusalem as that was when Peter was made head of Christ Church on earth. And Peter eventually became the Bishop of Rome and it was Constantine who actually created the idea of the Head of the Church reside in Greece when he renamed the City there Constantinople and planned to move the empire out of Rome to there and at one point declared it the see of Peter but the Western Bishops refused to do it so the seed of rebellion was planted
The Eastern Orthodox church traces its lineage back to the Apostles.. when they founded the Churches in Jerusalem and Constaninople. HOWEVER, at that time.. the Eastern Orthodox church didn't exist, it was part of the Catholic or simply the Christian religion. So while the Eastern Orthodox can trace it roots back to Apostles.. it can't trace its EXISTENCE back to that time.
The Catholic church can both trace its heritage as well as its existence back that far, so it is historically the first.
Also, the Eastern Orthodox, although autonomous, still recognizes the catholic church as first and the primacy of Peter as the head of the Catholic religion.
There is no historical record of an Orthodox Church until the 11Th Century.
The Roman Catholic Church even before the Second Vatican Council always considered it a duty of the highest rank to seek full unity with estranged communions of fellow-Christians, and at the same time to reject what it saw as promiscuous and false union that would mean being unfaithful to or glossing over the teaching of Sacred Scripture and Tradition. But the main stress was laid on this second aspect, as exemplified in canon 1258 of the 1917 Code of Canon Law:
The Roman Catholic Church has, since the Second Vatican Council, reached out to Christian bodies, seeking reconciliation to the greatest degree possible.
Of course, there were many differences, as others have pointed out. But there were some similarities, such as the priest facing the altar to lead the people in prayer. I am told that some older Catholics recognize a sense of awe and mystery in Orthodox worship that is hard to find in modern Catholicism.
as I understand, the EOC is a Catholic church, a universal church same as the Catholic roman and eastern churches. The only difference is the Papal succession which the EOC was opposed to and their eastern rites recited in their particular language.
Otherwise, they are per SE catholic, as founded by apostles St Mark, Andrew and Ignatius.