GetReligion, which tracks the coverage of religion in the media, reports on a case in which reporter Ann Rodgers had to explain the 1054 split in one sentence. Here is how Rodgers does it:
Orthodoxy developed in Eastern Europe and Asia when Christianity split into Orthodoxy and Catholicism in 1054, primarily due to conflict over papal authority.
Personally, I don’t think this is too bad. She doesn’t say that either Orthodoxy or Catholicism “started” in 1054, just that Orthodoxy “developed” after the split. The phrase “Christianity split into Orthodoxy and Catholicism” is problematic, but can be interpreted in a favorable light if one sees those terms as simply representing “Eastern” and “Western” Christianity. Here is how Rodgers explains her sentence:
It was something worked out on the fly when an editor asked for a very, very short explanation of Orthodox history. What I was trying to do was avoid saying that Orthodoxy split from Catholicism or vice versa. If you’re going to say that Orthodoxy dates to the first century you’re correct, but it was developing jointly with what became Catholicism. In 1054 they began to officially develop separately.
I think that is a fair attempt in such a short amount of space. Of course, the historical reality is that Eastern and Western Christianity began to develop separately long before 1054, and the events of that year were but a blip on the radar in relation to the history of the schism. But how do you condense such a complex subject into one sentence?
Update: In the comments Brother Charles comes up with what I think is a very good one sentence description:
“In 1054 the Body of Christ was broken and henceforth all Christians have Jesus’ own dying wish for unity on their conscience. (John 17:21)”