Why is Martin Luthers work significant?

Answer 1

Martin Luther helped start the reformation of the Catholic church. On October 31, 1517, Luther posted his 95 theses on the door of the Whitenburg Cathedral (which seems rather bold; however, many people would post things on church doors--a lot like how people post discussion topics on a forum) that discussed the sale of indulgences. (An indulgence is payment of a sin--much like a penance--and they were bought to save people from purgatory. The sale of indulgences was used to fund the construction of St. Peter's Cathedral, sold at different prices to people of different social statuses, and also sold for people that had already died.) Luther taught that salvation was by faith alone and that scripture was the final authority for Christians, not the pope.

Answer 2

Because many princes used Martin Luther and his work as an excuse to leave the Catholic Church and thus deny the sacraments of Our Blessed Lord, Jesus Christ, to their people.