What caused ancient Christianity to split into the Roman Catholic Church and Greek Orthodox Church?

In a nutshell ,the Greek churches were led from Constantinople,the seat of the newer Eastern Roman Empire and the western chuches from Rome. In time their cultures

diverged more and more in language, ritual and theological nuance. There is a long

wearisome history of various insults and political rivalry,ecclesiatical and not as well

as doctrinal and scriptural dispute.

This has often grieved thinkers on both sides mindful of the shared tradition.

As late as 1439 in Council in Florence the churches reunited only to resplit shorly

afterward.

The state of aggrieved separation persists.