The Reformation of course was a dispute.  There is a difficulty when speaking of this epochal event in saying too much or too little.  Here is an explanation in 85 words.

“This dispute has to do with the highest and chief article of all Christian doctrine (Justification}, so that much indeed depends on this article, which also serves preeminently to give a clear, correct understanding of the whole Sacred Scripture and alone points the way to the unutterable treasure and the true knowledge of Christ, and also alone opens the door to the whole Bible, without which article no poor conscience can have a constant, certain consolation or know the riches of the grace of Christ.”  Apology to the Augsburg Confession IV