Luther reconverted to the Roman Church on his deathbed? No he didn't. I receive many Google visits to this blog from people searching for information on "Did Luther Recant on His Deathbed?"
I recently came across this related section from Philip Schaff's History of the Christian Church vol. 8 (pp. 827-828) on the deaths of the major Protestant Reformers from what Schaff calls "fanatical Romanists." I've added some hyper-links to Schaff's text of the sources he mentions.
NOTE. A CALUMNY.
It is painful to notice that sectarian hatred and malice followed the Reformers to their death-beds. Fanatical Romanists represented Zwingli’s heroic death as a judgment of God, and invented the myths that Oecolampadius committed suicide and was carried off by the devil; that Luther hung himself by his handkerchief on the bed-post and emitted a horrible stench; and that Calvin died in despair.
The myth of Luther’s suicide was soberly and malignantly repeated by an ultramontane priest (Majunke, editor of the "Germania" in Berlin), and gave rise to a lively controversy in 1890. It must be added, however, that learned and honest Catholics indignantly protested against the calumny. (Cf. my article, Did Luther commit Suicide? in "Magazine of Christian Literature," New York, for December, 1890.)
As to Calvin, it is quite probable that his body, broken by so many diseases, soon showed signs of decay, which put a stop to the reception of strangers, and may have given rise to some "calumnies," of which Beza vaguely speaks. But it was not till fifteen years after his death, that Bolsec, the Apostate monk, fastened upon Calvin’s youth an odious vice (see above, p. 302), and spread the report that he died of a terrible malady,—that of being eaten by worms,—with which the just judgment of God destroys His enemies. He adds that Calvin even invoked the devils and cursed his studies and writings. ("Il mourut invoquant les diables … . Même il maudissait l’heure qu’il avait jamais étudié et écrit.") But he gives no authority, living or dead.
Audin (Life of Calvin, p. 532, Engl. transl.) repeats this infamous fabrication with some variations and dramatic embellishments, on the alleged testimony of an unknown student, who, as he says, sneaked into the death-chamber, lifted the black cloth from the face of Calvin and reported: "Calvinus in desperatione furiens vitam obiit turpissimo et faedissimo morbo quem Deus rebellibus et maledictis comminatus est, prius excruciatus et consumptus, quod ego verissime attestari audeo, qui funestum et tragicum illius exitum et exitium his meis oculis praesens aspexi. Joann. Harennius, apud Pet. Cutzenum!"
We regret to say that a Roman Catholic archbishop, Dr. Spalding, whose work on the Reformation gives no evidence of any acquaintance with the writings of Calvin or Beza, retails the slanders of Bolsec and Audin, and informs American readers that Calvin was "a very Nero" and "a monster of impurity and iniquity!" (See above, § 110, p. 520.)
Calvin’s whole life and writings, his testament, and dying words to the senators and ministers of Geneva, and the minute account of his death by his friend Beza, who was with him till his last moments, ought to be sufficient to convince even the most incredulous who is not incurably blinded by bigotry.