Complex sentence: Although the proportion of the European population rebelling against Catholic, Lutheran and Zwinglian churches was tiny, the literature on the Radical Reformation is vast, partly as a result of the proliferation of the Radical Reformation teachings in the United States.
Split into simpler sentences: Although the proportion of the European population was rebelling against Catholic teachings, Lutheran and Zwinglian churches were tiny. The literature on the Radical Reformation is vast, partly as a result of the proliferation of the Radical Reformation teachings in the United States.