Was John Knox an important historical figure or just a great author?

Knox is considered the Father of the Protestant Reformation in Scotland, so he is a significant historical figure. There is a substantial amount of information available at... http://en.wikipedia.org/wiki/John_KnoxWas John Knox an important historical figure or just a great author?
He played a material role in the Reformation in ScotlandWas John Knox an important historical figure or just a great author?
In Scotland the Reformation is associated with the name of John Knox, who declared that one celebration of the mass is worse than a cup of poison. He faced the very real threat that Mary, Queen of Scots, would do for Scotland what Mary Tudor had done for England. Therefore Knox defied her to her face in matters of religion and, though a commoner, addressed her as if he were all Scotland. He very nearly was, because in the period prior to 1560 many an obscure evangelist had converted the lowlands largely to the religion of John Calvin. The church had been given a Presbyterian structure, culminating in a General Assembly, which had actually as great and perhaps a greater influence than the Parliament. Because of her follies, and very probably her crimes (complicity in the murder of her husband), Mary had to seek asylum in England. There she became the focus of plots on the life of Elizabeth until Parliament decreed her execution. Presbyterianism came to be established in Scotland, and this very fact alone made possible the union of Scotland with England. Union of Protestant England with a Catholic Scotland would have been unthinkable.