Why the sacramental break between East and West?

Well-educated Catholics know a thing or two about why the Great Schism, separating the Eastern and Western branches of Christianity, occurred in the eleventh century. But most of us know just that -- only a thing or two. I'll include myself in that group: when students ask me, I say something about the filioque and papal authority.

A recent piece by historian George Demacopoulos posted on the blog of the Greek Archdiocese of North America shows the importance of contextualizing the split in the fuller contexts of canon law and the Crusades. He asks: "[H]ow exactly did it come to pass that the Orthodox Church forbid sacramental union (baptisms, marriages, the Eucharist, etc.) with Western Christians in the first place?"