What was the name of the Church up until 1054 AD, not the Catholic Church and not Orthodox Church. It was just called the Church. The Bishop of Rome was the first Protestant which is called the Pope today in the West. The reason for the split from East and West was multifaceted, however there were two main reasons.
The first was the supremacy of the Pope would make all final decisions over all doctrines with no higher accountability. This was not what Christ intended. But I might add that the Eastern Church does recognize the primacy of the Pope or as I would say the Bishop of Rome over his region, but not the supremacy over all regions of the world. The Roman Church has not been in communion with the East since then.
Second reason is the changing of the Nicene Creed which adds the words that the Holy Spirit proceeded from the father “and the Son”, in Latin this is called the (filioque). Not from the father alone. I don't think the issue itself was the fact that words were added to the creed. The fact is, that the Roman Church and the supremacy of the Pope went above and beyond without any church councils to make decisions.
Since then there have been smaller schisms within the Western Church. It makes sense since the Protestants and their Reformers knew one thing, they didn’t want Rome and its corrupt Popes. This is how the East understands the reformation and would agree, however without realizing it, this schism continued to separate the brothers from East and West, eventually the language of Greek and Latin became estranged and many doctrines of the east continued in the west with many mistranslated texts, some intentional and some not because of the lack of learned Greek speaking Bishops to help with translations.
“Orthodox see History in another perspective, Consider, for example, the Orthodox attitude towards western religious disputes. In the west it is usual to think of Roman Catholicism and Protestantism as opposite extremes; but to an Orthodox they appear as two sides of the same coin. Khomiakov calls the Pope ‘the first Protestant’, ‘the father of German rationalism’; and by the same token he would doubtless have considered the Christian Scientist and eccentric Roman Catholic. ‘How are we to arrest the pernicious effects of Protestantism?’ he was asked by a High Church Anglican when visiting Oxford in 1847; to which he replied: ‘Shake off your Roman Catholicism.’ In the eyes of the Russian theologian, the two things went hand in hand’ both alike share the same assumptions, for Protestantism was hatched from the egg which Rome had laid." - The Orthodox Church, by Timothy Ware
Many in the west have a disconnect in church history, including myself, I had a massive gap in my historical understand of the Church. I may have at times in my ignorance and lack of understanding persecute those who did not look like my local church here in America. The reality is when I began to do further research into church history I found that even though the Catholic Church may have retained an almost outward structure of the original church, they most certainly did not maintain its teachings. As for the Protestants, they retain almost nothing except for the essentials, for which I am forever grateful. However there have been some abhorrent branches that do not maintain the essentials such as Jehovah Witnesses, Mormonism and a few others. I must add , I have learned a great deal from my Protestant teachers and that I am grateful for as well, I love them dearly and will always have an open door to service. This is what our Lord would want anyways, to unite and not divide.