John Calvin was born a Roman Catholic in 1509. When he was eight, the Lutheran Reformation started in Germany. When he was twelve, he became a Roman Catholic Chaplain. And when he was eighteen, he was appointed a Curate. At that time, the religious young Calvin had no appreciative interest in the Protestant Reformation whatsoever.
Upon hearing of the Reformation, Calvin instinctively disliked it. He reacted against it. He inquisitively read the Bible in order to refute Luther and to confirm his own Roman Catholicism. But in so doing, by the grace of God Calvin was suddenly converted to Christ.