The religious zeal as well as the moral earnestness of the age was naturally drawn to the Protestant side.

As the sect was persecuted, no one joined it save from conscientious motives.

Against the laziness or the corruption of the prelates, too proud or too indifferent to give a reason for their faith, the innovators opposed a tireless energy in season and out of season; against the scandals of the court and the immorality of the clergy they raised the banner of a new and stern morality; to the fires of martyrdom they replied with the fires of burning faith.
The missionaries of the Calvinists were very largely drawn from converted members of the clergy, both secular and regular, and from those who had made a profession of teaching.

For the purposes of propaganda these were precisely the classes most fitted by training and habit to arouse and instruct the people.

Tracts were multiplied, and they enjoyed, notwithstanding the censures of the Sorbonne, a brisk circulation.