[jmopp]

Yes, but the Chalcedonian schism and the East-West schism were between churches who viewed themselves ostensibly as equals, or at least on a relatively equal footing — bishops leading one church against bishops leading another. The Protestant Reformation was more like a revolution: people fed up with the Church for whatever reason rebelling against it. There were antecedents, like the Lollards who had many of the same complaints the Protestants had, but their movements never stuck or spread in the same way that Protestantism did. That, I believe, can be attributed to the printing press