It's actually not quite so clear cut. 1053/1054 was when mutual excommunications between Rome and Constantinople happened, but (as the schism itself is evidence

It's actually not quite so clear cut. 1053/1054 was when mutual excommunications between Rome and Constantinople happened, but (as the schism itself is evidence of) Constantinople did not speak for the entire church, and other eastern sees continued communion with Rome for quite some time afterward. https://kalebatlantaprime.medium.com/the-great-schism-was-in-1285-572890aa8af0 https://kalebatlantaprime.medium.com/the-great-schism-was-in...