No difference in their beliefs. They are both part of the Eastern Orthodox Church, but the Antiochians are mainly Orthodox people from Lebanon, and the Greeks are mainly Orthodox people from Greece.
The Pope is the leader of the Roman Catholic Church. The Partriarchs are leaders of other Catholic faiths, such as Greek Rite, Russian Orthodox, Byzantine Rite, Coptic Rite and so forth. Some consider themselves subject to the Pope, and some do not.
Catholic Confirmation usually takes place when the young person is between the ages of 12 - 15 years. Orthodox Chrismation usually takes place after the baby is Baptized.
Western Europe is mostly Catholic while Russia is Orthodox.
The main difference is the authority of the pope. Catholics accept it, Protestants and Orthodox don't. There are some differences in the cannon (list of books) included in the Old Testament (although they all have the same New Testament). There are several different types of Protestant religions (Lutheran, Methodist, Anglican, etc) which have differences between themselves and differences between Catholic/Orthodox. So complicated to get into more specifics.
By the time, Great Schism the patriarch of Contantinople named Michael Cerularius dispute with Pope Leo IX. They differed with Roman church in their Eucharist. They do not use unleavened bread.
The difference is between truth (Orthodox) and error (Baptists).
Christianity, Roman Catholic and Orthodox, and Islam
Roman Catholic AnswerThe Catholic would need to apply to his priest for an annulment, I don't know what the regulations are for the Orthodox.
The Roman Catholic Church is normally known for using fresco's and Statues in their churches. Whereas The Eastern Orthodox Church uses mosaics and icons, with a small percentage of the time they will also use fresco's .
Western Europe is majority Catholic whiel Russia is majority Eastern Orthodox. Both are branches of Christianity, however.
At this point in time, the only meeting that the Patriarch Athenagoras could have with anyone would be God, as he died many years ago, in the 1970's. However, he did meet with Pope Paul VI back in 1969, while he was still alive.