What was the underlying disagreement that Martin Luther had when it came to the Catholic church?

He believed the Catholic Church got it wrong on salvation

Luther believed people were saved by faith alone and that this was the summary of all Christian doctrine, and that the Catholic Church of his day had got this wrong. ... "Luther's phrase 'faith alone' is true, if it is not opposed to faith in charity, in love.

Explanation:

the process is called revolution because it was a process of great economic-social transformations that began in england in the xviii century.

the industrial mode of production spread throughout much of the northern hemisphere throughout the xix and early xx centuries.

the effect of this revolution was the distance between the countries, with respect to economic and political power.   after all, not all industrialized at the same time, remaining in the condition of suppliers of raw materials and agricultural products to the industrialized countries.

these differences mark to this day the nations of the world that are divided between developed and developing countries. one way to measure whether a country is advanced is to assess how industrialized it is.