Source: “Why Europeans Left,” Dr. Gayle Olson-Raymer, Professor of History, Humboldt State University. December 2014.
For about 1,500 years, Christians in Western Europe mostly belonged to the Roman Catholic Church, which was centered in Rome. The church was a major political and military power in Western Europe. The pope, as head of the church, was the spiritual leader and his views on religious doctrine were regarded as final. Consequently, popes used their power to defend and expand the church’s influence and wealth.
Between 110 and 1500, the Church and the popes increased their power and control over the lives of Europeans by requiring tithes, taxes, church fees, and payments to support numerous clergymen… Catholic priests were also very powerful in the lives of everyday Europeans…
At the beginning of the 16th century, the political power of the kings was increasing in most Western European nations. …[At the same time, the] Catholic Church [continued to wield immense power] and as the ambitions of popes increased, many believed the church took advantage of them. [Germans, in particular,] complained that the church impoverished the common people while enriching Rome and many felt the church was more interested in wealth and power than in the spiritual needs of the people…
[In 1517,] Martin Luther, an obscure Catholic priest who lived in northern Germany changed the face of Europe forever. [Luther demanded radical changes to the idea of salvation and the practices of the Church. His followers became known as Protestants and eventually began practicing their version of Christianity separately from Catholics. Other splits within Protestantism came later.]
Religious reform shattered the unity of European Christianity: Spain, Italy, and Ireland remained firmly Catholic; France, England, Scotland, Switzerland, and the Netherlands gained a substantial following for Calvinism; while Germany and Scandinavia became largely Lutheran. [Calvinism and Lutheranism are branches of Protestantism.]
The competing religious loyalties that emerged resulted in brutal wars and internal uprising that wracked 16th Century Europe as Protestant and Catholic antagonists slaughtered each other in the name of Christianity. The legacy of what became known as the Protestant Reformation intensified European interest in colonization. Many Europeans, especially the English, who embraced the new Protestant faiths… saw the "New World" as a safe haven for practicing their religion. [Additionally, both Catholic and Protestant rulers saw it as their duty to spread their branch of Christianity to new peoples.]