Forerunners Of The Reformation

Gavin Ortlund just put out a good video on reform groups in the centuries leading up to the Reformation, especially the Waldensians. You can find some material on medieval agreements with Protestantism in our archives, such as some discussions of medieval sources in my article on the history of sola fide. I'm more familiar with the patristic era than the medieval era, but I've occasionally addressed medieval issues, in the article just linked and elsewhere. Go here for an example of a Catholic scholar acknowledging belief in some of the Protestant solas prior to the Reformation. A different, but related issue is how well some Protestant beliefs were initially received at the time of the Reformation. See here. If Protestantism is as much of a departure from earlier history as its critics often claim, why do we see groups like the ones Gavin Ortlund discusses and beliefs and circumstances like the ones discussed in my articles linked above?