the Great Schism

The Great Schism is one of the most important historical events of the medieval era.

Q: why was it important?

A: The Great Schism divided the Catholic and Orthodox Churches into the Roman Catholic (Western), and the Greek Catholic or the Greek Orthodox Churches.

Q: when was this?

A: the Great Schism is traditionally dated to 1054, in the eleventh century A.D.

Now it is difficult to determine the point at which the split became a fixed.