John Calvin's Commentary On The Psalms Volume 1, contains a brief autobiographical account of John Calvin's embracing of the Reformation, and discusses the persecutions that caused him to write the first edition of the Institutes of the Christian Religion 1535AD. According to the following Preface quotation, certain Anabaptists and participants of the Radical Reformation had incited persecutions of all the Reformers, and that many people had been burned to death for advancing the Reformation. 

Now, if my readers derive any fruit and advantage from the labor which I have bestowed in writing these Commentaries, I would have them to understand that the small measure of experience which I have had by the conflicts with which the Lord has exercised me, has in no ordinary degree assisted me, not only in applying to present use whatever instruction could be gathered from these divine compositions, but also in more easily comprehending the design of each of the writers. And as David holds the principal place among them, it has greatly aided me in understanding more fully the complaints made by him of the internal afflictions which the Church had to sustain through those who gave themselves out to be her members, that I had suffered the same or similar things from the domestic enemies of the Church. For although I follow David at a great distance, and come far short of equaling him; or rather, although in aspiring slowly and with great difficulty to attain to the many virtues in which he excelled, I still feel myself tarnished with the contrary vices; yet if I have any things in common with him, I have no hesitation in comparing myself with him.

In reading the instances of his faith, patience, fervor, zeal, and integrity, it has, as it ought, drawn from me unnumbered groans and sighs, that I am so far from approaching them; but it has, notwithstanding, been of very great advantage to me to behold in him as in a mirror, both the commencement of my calling, and the continued course of my function; so that I know the more assuredly, that whatever that most illustrious king and prophet suffered, was exhibited to me by God as an example for imitation. My condition, no doubt, is much inferior to his, and it is unnecessary for me to stay to show this. But as he was taken from the sheepfold, and elevated to the rank of supreme authority; so God having taken me from my originally obscure and humble condition, has reckoned me worthy of being invested with the honorable office of a preacher and minister of the gospel. When I was as yet a very little boy, my father had destined me for the study of theology. But afterwards when he considered that the legal profession commonly raised those who followed it to wealth this prospect induced him suddenly to change his purpose. Thus it came to pass, that I was withdrawn from the study of philosophy, and was put to the study of law.

To this pursuit I endeavored faithfully to apply myself in obedience to the will of my father; but God, by the secret guidance of his providence, at length gave a different direction to my course. And first, since I was too obstinately devoted to the superstitions of Popery to be easily extricated from so profound an abyss of mire, God by a sudden conversion subdued and brought my mind to a teachable frame, which was more hardened in such matters than might have been expected from one at my early period of life. Having thus received some taste and knowledge of true godliness I was immediately inflamed with so intense a desire to make progress therein, that although I did not altogether leave off other studies, I yet pursued them with less ardor. I was quite surprised to find that before a year had elapsed, all who had any desire after purer doctrine were continually coming to me to learn, although I myself was as yet but a mere novice and tyro. Being of a disposition somewhat unpolished and bashful, which led me always to love the shade and retirement, I then began to seek some secluded corner where I might be withdrawn from the public view; but so far from being able to accomplish the object of my be desire, all my retreats were like public schools. In short, whilst my one great object was to live in seclusion without being known, God so led me about through different turnings and changes, that he never permitted me to rest in any place, until, in spite of my natural disposition, he brought me forth to public notice.

Leaving my native country, France, I in fact retired into Germany, expressly for the purpose of being able there to enjoy in some obscure corner the repose which I had always desired, and which had been so long denied me. But lo! whilst I lay hidden at Basle, and known only to a few people, many faithful and holy persons were burnt alive in France; and the report of these burnings having reached foreign nations, they excited the strongest disapprobation among a great part of the Germans, whose indignation was kindled against the authors of such tyranny. In order to allay this indignation, certain wicked and lying pamphlets were circulated, stating that none were treated with such cruelty but Anabaptists and seditious persons, who by their perverse ravings and false opinions, were overthrowing not only religion but also all civil order. Observing that the object which these instruments of the court aimed at by their disguises, was not only that the disgrace of shedding so much innocent blood might remain buried under the false charges and calumnies which they brought against the holy martyrs after their death, but also, that afterwards they might be able to proceed to the utmost extremity in murdering the poor saints without exciting compassion towards them in the breasts of any, it appeared to me, that unless I opposed them to the utmost of my ability, my silence could not be vindicated from the charge of cowardice and treachery. This was the consideration which induced me to publish my Institute of the Christian Religion. My objects were, first, to prove that these reports were false and calumnious, and thus to vindicate my brethren, whose death was precious in the sight of the Lord; and next, that as the same cruelties might very soon after be exercised against many unhappy individuals, foreign nations might be touched with at least some compassion towards them and solicitude about them.

When it was then published, it was not that copious and labored work which it now is, but only a small treatise containing a summary of the principal truths of the Christian religion, and it was published with no other design than that men might know what was the faith held by those whom I saw basely and wickedly defamed by those flagitious and perfidious flatterers. That my object was not to acquire fame, appeared from this, that immediately after I left Basle, and particularly from the fact that nobody there knew that I was the author. Wherever else I have gone, I have taken care to conceal that I was the author of that performance; and I had resolved to continue in the same privacy and obscurity, until at length William Farel detained me at Geneva, not so much by counsel and exhortation, as by a dreadful imprecation, which I felt to be as if God had from heaven laid his mighty hand upon me to arrest me. As the most direct road to Strasburg, to which I then intended to retire, was shut up by the wars, I had resolved to pass quickly by Geneva, without staying longer than a single night in that city.

A little before this, Popery had been driven from it by the exertions of the excellent person whom I have named, and Peter Viret; but matters were not yet brought to a settled state, and the city was divided into unholy and dangerous factions. Then an individual who now basely apostatised and returned to the Papists, discovered me and made me known to others. Upon this, Farel, who burned with an extraordinary zeal to advance the gospel, immediately strained every nerve to detain me. And after having learned that my heart was set upon devoting myself to private studies for which I wished to keep myself free from other pursuits, and finding that he gained nothing by entreaties, he proceeded to utter an imprecation that God would curse my retirement, and the tranquillity of the studies which I sought, if I should withdraw and refuse to give assistance, when the necessity was so urgent. By this imprecation I was so stricken with terror, that I desisted from the journey which I had undertaken; but sensible of my natural bashfulness and timidity, I would not bring myself under obligation to discharge any particular office. After that, four months had scarcely elapsed, when, on the one hand, the Anabaptists began to assail us, and, on the other, a certain wicked apostate, who being secretly supported by the influence of some of the magistrates of the city, was thus enabled to give us a great deal of trouble. At the same time, a succession of dissensions fell out in the city ¹³ which strangely afflicted us.

Being, as I acknowledge, naturally of a timid, softer and pusillanimous disposition, I was compelled to encounter these violent tempests as part of my early training; and although I did not sink under them, yet I was not sustained by such greatness of mind, as not to rejoice more than it became me, when, in consequence of certain commotions, I was banished from Geneva. By this means set at liberty and loosed from the tie of my vocation, I resolved to live in a private station, free from the burden and cares of any public charge, when that most excellent servant of Christ, Martin Bucer, employing a similar kind of remonstrance and protestation as that to which Farel had recourse before, drew me back to a new station. Alarmed by the example of Jonas which he set before me, I still continued in the work of teaching. And although I always continued like myself, studiously avoiding celebrity; ¹⁴ yet I was carried, I know not how, as it were by force to the Imperial assemblies, where, willing or unwilling, I was under the necessity of appearing before the eyes of many. Afterwards, when the Lord having compassion on this city, had allayed the hurtful agitations and broils which prevailed in it, and by his wonderful power had defeated both the wicked counsels and the sanguinary attempts of the disturbers of the Republic, necessity was imposed upon me of returning to my former charge, contrary to my desire and inclination.

The welfare of this church, it is true, lay so near my heart, that for its sake I would not have hesitated to lay down my life; but my timidity nevertheless suggested to me many reasons for excusing myself from again willingly taking upon my shoulders so heavy a burden. At length, however, a solemn and conscientious regard to my duty, prevailed with me to consent to return to the flock from which I had been torn; but with what grief, tears, great anxiety and distress I did this, the Lord is my best witness, and many godly persons who would have wished to see me delivered from this painful state, had it not been that that which I feared, and which made me give my consent, prevented them and shut their mouths. Were I to narrate the various conflicts by which the Lord has exercised me since that time, and by what trials he has proved me, it would make a long history. But that I may not become tedious to my readers by a waste of words, I shall content myself with repeating briefly what I have touched upon a little before, that in considering the whole course of the life of David, ¹⁵ it seemed to me that by his own footsteps he showed me the way, and from this I have experienced no small consolation.

John Calvin, Commentary On The Psalms, Vol 1, Preface,
http://www.ccel.org/ccel/calvin/calcom08.vi.html#vi-p7