Final answer:
The splintering of the Christian faith from one primary church into multiple denominations in Europe was caused by the Protestant Reformation in the 16th century, led by figures like Martin Luther.
Step-by-step explanation:
The event that changed Europe by splintering the Christian faith from one primary church into multiple churches or denominations was the Protestant Reformation. This reformation began in the 16th century when Martin Luther and others challenged the authorities of the Catholic Church, leading to the rise of Protestant denominations such as Lutheranism, Calvinism, and Anabaptism.
These movements found significant support in northern Europe and other parts, creating a religious schism that forever changed the Christian landscape of Europe.
Luther's doctrine emphasizing faith alone for salvation and scripture as the only source of Christian authority, combined with the discontent with the Catholic Church's practices, facilitated the spread of Protestant reformations. The invention of the printing press allowed these ideas to disseminate more broadly, helping to establish various new Christian denominations throughout Europe.
While the Roman Catholic Church attempted to respond with its own reformation through the Council of Trent, the Protestant churches continued to gain followers. This division in Christianity led to religious conflicts and wars across Europe as Catholics and Protestants each sought to defend their interpretation of the faith.