Jaroslav Jan Pelikan (December 17, 1923–May 13, 2006) was a scholar in the history of Christianity, Christian theology and medieval intellectual history.

Pelikan was born in Akron, Ohio, to a Slovak father and mother, Jaroslav Jan Pelikan Sr. and Anna Buzekova Pelikan. His father was pastor of Trinity Slovak Lutheran Church in Chicago, Illinois, and his paternal grandfather a bishop of the Synod of Evangelical Lutheran Churches then known as the Slovak Lutheran Church in America.

According to family members, Pelikan's mother taught him how to use a typewriter when he was three years old, as he could not yet hold a pen properly but wanted to write. A polyglot, Pelikan's facility with languages may be traced to his multilingual childhood and early training. That linguistic facility was to serve him in the career he ultimately chose (after contemplating becoming a concert pianist)--as a historian of Christian doctrine. He did not confine his studies to Roman Catholic and Protestant theological history, but also embraced that of the Christian East.

 Martin Luther (help·info) (10 November 1483 – 18 February 1546) was a German monk, priest, professor of theology and iconic figure of the Protestant Reformation. He strongly disputed the claim that freedom from God's punishment for sin could be purchased with money. He confronted indulgence salesman Johann Tetzel with his Ninety-Five Theses in 1517. His refusal to retract all of his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms in 1521 resulted in his excommunication by the pope and condemnation as an outlaw by the Emperor.

Luther taught that salvation is not earned by good deeds but received only as a free gift of God's grace through faith in Jesus Christ as redeemer from sin. His theology challenged the authority of the Pope of the Roman Catholic Church by teaching that the Bible is the only source of divinely revealed knowledge and opposed sacerdotalism by considering all baptized Christians to be a holy priesthood. Those who identify with Luther's teachings are called Lutherans.