What significant event occurred in 1054 regarding the Roman Catholic Church?

The event that took place in 1054 was the Great Schism, which was a pivotal moment in the history of Christianity. This schism represented the formal split between the Roman Catholic Church based in Rome and the Orthodox Church based in Constantinople. The division stemmed from theological, political, and cultural differences that had developed over centuries, including disputes over papal authority and the addition of the "Filioque" clause in the Nicene Creed.

The Great Schism is significant because it not only shaped the religious landscape of Europe but also had profound implications for the political and cultural alignments within Christendom. The schism solidified two distinct branches of Christianity that would evolve separately, influencing the development of religious thought, ecclesiastical governance, and the nature of worship in the Western and Eastern Christian traditions.

The other options outline important historical developments, but they do not pertain to the key event of 1054. The establishment of universities occurred later in the medieval period, and the start of the Crusades was in the late 11th century, while the formation of Protestantism took place much later in the 16th century during the Reformation.