What were the core principles of the first Protestant denominations that led to the period known as the Reformation? How did further Protestant denominations differ from the original ideas of Martin Luther?

All of the solae show up in various writings by the Protestant Reformers, but they are not catalogued together by any. In 1916, Lutheran scholar Theodore Engelder published an article titled "The Three Principles of the Reformation: Sola Scriptura, Sola Gratia, Sola Fides

Explanation:

Luther believed this because he thought one should ask God what to do for sins rather than just do good works. Calvin believed this because he thought people were already chosen for salvation so good works would make no difference. ... Martin Luther believed in the need for reformation of the Roman Catholic Church.

martin luther believed that selling indulgences was wrong and gave people a license to sin. the roman catholic church used the practice of indulgences to raise money for major building projects.