Bot really! It was the filoque clause that separated the RCC & the Orthodox Church!
I just googled this, and it is listed as a cause. I studied this in church history and in theology. Here is what I learned.
"The primary causes of the Schism were disputes over papal authority—the Pope claimed he held authority over the four Eastern Greek-speaking patriarchs, and over the insertion of the filioque clause into the Nicene Creed."
https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/e/East-West_Schism.htm#:~:text=The primary causes of the,clause into the Nicene Creed.
A more detailed account is found in a Wikipedia entry, which corresponds to what I learned.
"Filioque, Latin for "and (from) the Son", was added in Western Christianity to the Latin text of the
Nicene-Constantinopolitan Creed, which also varies from the original Greek text in having the additional phrase Deum de Deo (God from God)
[47][48] and in using the singular "I believe" (Latin, Credo, Greek Πιστεύω) instead of the original "We believe" (Greek Πιστεύομεν),
[48] which
Oriental Orthodoxy preserves.
[c] The
Assyrian Church of the East, which is in communion neither with the Eastern Orthodox Church nor with Oriental Orthodoxy, uses "We believe".
[53]
Filioque states that the Holy Spirit proceeds from the Son as well as from the Father, a doctrine accepted by the
Catholic Church,
[54] by
Anglicanism[55] and by
Protestant churches in general.
[d] Christians of these groups generally include it when reciting the Nicene Creed. Nonetheless, these groups recognize that Filioque is not part of the original text established at the
First Council of Constantinople in 381,
[59]and they do not demand that others too should use it when saying the Creed.
[60] Indeed, the Catholic Church does not add the phrase corresponding to Filioque (καὶ τοῦ Υἱοῦ) to the Greek text of the Creed, even in the
liturgy for
Latin Rite Catholics.
[61]
At the
879–880 Council of Constantinople the Eastern Orthodox Church anathematized the Filioque phrase, "as a novelty and augmentation of the Creed", and in their 1848 encyclical the Eastern Patriarchs spoke of it as a heresy.
[62] It was qualified as such by some of the Eastern Orthodox Church's saints, including
Photios I of Constantinople,
Mark of Ephesus, and
Gregory Palamas, who have been called the Three Pillars of Orthodoxy. The Eastern church believes by the Western church inserting the Filioque unilaterally (without consulting or holding council with the East) into the Creed, that the Western Church broke communion with the East."
https://en.m.wikipedia.org/wiki/East–West_Schism
Theological speaking, the filioque clause is by far the most important cause of the Schism.