Eastern Orthodoxy: Article from a Catholic apologist site on the Great Schism between Rome and Constantinople.
Eastern Schism: Article from the Catholic Encyclopedia.
Filioque Controversy: Three articles from Protestant and Orthodox perspectives.
Great Schism: Several articles from a Protestant perspective on the Great Schism that divided the Catholic and Orthodox Churches.
Notes on the Filioque Clause Controversy: An essay on the development of this dispute.
Why Is There an Eastern Question?: Article which gives background information on the situation in the Balkans from a Catholic view.