It is commonly thought that there was only the Catholic church from the 5th century to the 16th, when reformers such as Luther and Calvin came along and broke of from them.  But this is entirely untrue.  During the entirety of Christian History, there has always been a faithful remnant.  A shining example of this is the Waldensians, who began with Peter Waldo in the 1100's.  And as the Apostle Paul says, "all those who live godly in Christ Jesus shall suffer persecution," the Waldenses, living righteously were no exception to that rule.