I know I harp on church history- three branches - western (Catholic/Protestant), Byzantine (Eastern Orthodox) and Oriental Orthodox. And that the Catholic Church has Byzantine and Oriental rites. And you go "there goes MJ again." But today the BBC has an article that show why it matters politically: Pope Francis in historic talks with Russian Orthodox leader
A couple of excerpts for those who don't read the whole article:
The Russian Orthodox Church said earlier the "persecution of Christians" in the Middle East and North Africa would be the key theme.
The two leaders later signed a joint declaration on this issue.
and
Ahead of the meeting, the foreign policy chief of the Russian Orthodox Church, Metropolitan Illarion, said here were still differences between the two churches, in particular on western Ukraine.
One particular issue is the Ukrainian Greek Catholic Church, which follows eastern church rites but answers to the Holy See.
The Russian Orthodox Church has considered western Ukraine its traditional territory, resenting papal influence there.
So please, if you don't know anything but Western Church history, please look at the history offerings of the Orthodox Logos group.