Voltaire was forty-two years of age, and already one of the most famous men of the day, when, in August 1736, he received a letter from the Crown Prince of Prussia. This letter was the first in a correspondence which was to last, with a few remarkable intervals, for a space of over forty years. It was written by a young man of twenty-four, of whose personal qualities very little was known, and whose importance seemed to lie simply in the fact that he was heir-apparent to one of the secondary European monarchies. Voltaire, however, was not the man to turn up his nose at royalty, in whatever form it might present itself; and it was moreover clear that the young prince had picked up at least a smattering of French culture, that he was genuinely anxious to become acquainted with the tendencies of modern thought, and, above all, that his admiration for the author of the Henriade and Zaïre was unbounded.
La douceur et le support [wrote Frederick] que vous marquez pour tous ceux qui se vouent aux arts et aux sciences, me font espérer que vous ne m'exclurez pas du nombre de ceux que vous trouvez dignes de vos instructions. Je nomme ainsi votre commerce de lettres, qui ne peut être que profitable à tout être pensant. J'ose même avancer, sans déroger au mérite d'autrui, que dans l'univers entier il n'y aurait pas d'exception à faire de ceux dont vous ne pourriez être le maître.
The great man was accordingly delighted; he replied with all that graceful affability of which he was a master, declared that his correspondent was 'un prince philosophe qui rendra les hommes heureux,' and showed that he meant business by plunging at once into a discussion of the metaphysical doctrines of 'le sieur Wolf,' whom Frederick had commended as 'le plus célèbre philosophe de nos jours.' For the next four years the correspondence continued on the lines thus laid down. It was a correspondence between a master and a pupil: Frederick, his passions divided between German philosophy and French poetry, poured out with equal copiousness disquisitions upon Free Will and la raison suffisante, odes sur la Flatterie, and epistles sur l'Humanité, while Voltaire kept the ball rolling with no less enormous philosophical replies, together with minute criticisms of His Royal Highness's mistakes in French metre and French orthography. Thus, though the interest of these early letters must have been intense to the young Prince, they have far too little personal flavour to be anything but extremely tedious to the reader of to-day. Only very occasionally is it possible to detect, amid the long and careful periods, some faint signs of feeling or of character. Voltaire's empressement seems to take on, once or twice, the colours of something like a real enthusiasm; and one notices that, after two years, Frederick's letters begin no longer with 'Monsieur' but with 'Mon cher ami,' which glides at last insensibly into 'Mon cher Voltaire'; though the careful poet continues with his 'Monseigneur' throughout. Then, on one occasion, Frederick makes a little avowal, which reads oddly in the light of future events.
Souffrez [he says] que je vous fasse mon caractère, afin que vous ne vous y mépreniez plus ... J'ai peu de mérite et peu de savoir; mais j'ai beaucoup de bonne volonté, et un fonds inépuisable d'estime et d'amitié pour les personnes d'une vertu distinguée, et avec cela je suis capable de toute la constance que la vraie amitié exige. J'ai assez de jugement pour vous rendre toute la justice que vous méritez; mais je n'en ai pas assez pour m'empêcher de faire de mauvais vers.
But this is exceptional; as a rule, elaborate compliments take the place of personal confessions; and, while Voltaire is never tired of comparing Frederick to Apollo, Alcibiades, and the youthful Marcus Aurelius, of proclaiming the rebirth of 'les talents de Virgile et les vertus d'Auguste,' or of declaring that 'Socrate ne m'est rien, c'est Frédéric que j'aime,' the Crown Prince is on his side ready with an equal flow of protestations, which sometimes rise to singular heights. 'Ne croyez pas,' he says, 'que je pousse mon scepticisime à outrance ... Je crois, par exemple, qu'il n'y a qu'un Dieu et qu'un Voltaire dans le monde; je crois encore que ce Dieu avait besoin dans ce siècle d'un Voltaire pour le rendre aimable.' Decidedly the Prince's compliments were too emphatic, and the poet's too ingenious; as Voltaire himself said afterwards, 'les épithètes ne nous coûtaient rien'; yet neither was without a little residue of sincerity. Frederick's admiration bordered upon the sentimental; and Voltaire had begun to allow himself to hope that some day, in a provincial German court, there might be found a crowned head devoting his life to philosophy, good sense, and the love of letters. Both were to receive a curious awakening.
In 1740 Frederick became King of Prussia, and a new epoch in the relations between the two men began. The next ten years were, on both sides, years of growing disillusionment. Voltaire very soon discovered that his phrase about 'un prince philosophe qui rendra les hommes heureux' was indeed a phrase and nothing more. His prince philosophe started out on a career of conquest, plunged all Europe into war, and turned Prussia into a great military power. Frederick, it appeared, was at once a far more important and a far more dangerous phenomenon than Voltaire had suspected. And, on the other hand, the matured mind of the King was not slow to perceive that the enthusiasm of the Prince needed a good deal of qualification. This change of view, was, indeed, remarkably rapid. Nothing is more striking than the alteration of the tone in Frederick's correspondence during the few months which followed his accession: the voice of the raw and inexperienced youth is heard no more, and its place is taken—at once and for ever—by the self-contained caustic utterance of an embittered man of the world. In this transformation it was only natural that the wondrous figure of Voltaire should lose some of its glitter—especially since Frederick now began to have the opportunity of inspecting that figure in the flesh with his own sharp eyes. The friends met three or four times, and it is noticeable that after each meeting there is a distinct coolness on the part of Frederick. He writes with a sudden brusqueness to accuse Voltaire of showing about his manuscripts, which, he says, had only been sent him on the condition of un secret inviolable. He writes to Jordan complaining of Voltaire's avarice in very stringent terms. 'Ton avare boira la lie de son insatiable désir de s'enrichir ... Son apparition de six jours me coûtera par journée cinq cent cinquante écus. C'est bien payer un fou; jamais bouffon de grand seigneur n'eut de pareils gages.' He declares that 'la cervelle du poète est aussi légère que le style de ses ouvrages,' and remarks sarcastically that he is indeed a man extraordinaire en tout.
Yet, while his opinion of Voltaire's character was rapidly growing more and more severe, his admiration of his talents remained undiminished. For, though he had dropped metaphysics when he came to the throne, Frederick could never drop his passion for French poetry; he recognised in Voltaire the unapproachable master of that absorbing art; and for years he had made up his mind that, some day or other, he would posséder—for so he put it—the author of the Henriade, would keep him at Berlin as the brightest ornament of his court, and, above all, would have him always ready at hand to put the final polish on his own verses. In the autumn of 1743 it seemed for a moment that his wish would be gratified. Voltaire spent a visit of several weeks in Berlin; he was dazzled by the graciousness of his reception and the splendour of his surroundings; and he began to listen to the honeyed overtures of the Prussian Majesty. The great obstacle to Frederick's desire was Voltaire's relationship with Madame du Châtelet. He had lived with her for more than ten years; he was attached to her by all the ties of friendship and gratitude; he had constantly declared that he would never leave her—no, not for all the seductions of princes. She would, it is true, have been willing to accompany Voltaire to Berlin; but such a solution would by no means have suited Frederick. He was not fond of ladies—even of ladies like Madame du Châtelet—learned enough to translate Newton and to discuss by the hour the niceties of the Leibnitzian philosophy; and he had determined to posséder Voltaire either completely or not at all. Voltaire, in spite of repeated temptations, had remained faithful; but now, for the first time, poor Madame du Châtelet began to be seriously alarmed. His letters from Berlin grew fewer and fewer, and more and more ambiguous; she knew nothing of his plans; 'il est ivre absolument' she burst out in her distress to d'Argental, one of his oldest friends. By every post she dreaded to learn at last that he had deserted her for ever. But suddenly Voltaire returned. The spell of Berlin had been broken, and he was at her feet once more.
What had happened was highly characteristic both of the Poet and of the King. Each had tried to play a trick on the other, and each had found the other out. The French Government had been anxious to obtain an insight into the diplomatic intentions of Frederick, in an unofficial way; Voltaire had offered his services, and it had been agreed that he should write to Frederick declaring that he was obliged to leave France for a time owing to the hostility of a member of the Government, the Bishop of Mirepoix, and asking for Frederick's hospitality. Frederick had not been taken in: though he had not disentangled the whole plot, he had perceived clearly enough that Voltaire's visit was in reality that of an agent of the French Government; he also thought he saw an opportunity of securing the desire of his heart. Voltaire, to give verisimilitude to his story, had, in his letter to Frederick, loaded the Bishop of Mirepoix with ridicule and abuse; and Frederick now secretly sent this letter to Mirepoix himself. His calculation was that Mirepoix would be so outraged that he would make it impossible for Voltaire ever to return to France; and in that case—well, Voltaire would have no other course open to him but to stay where he was, in Berlin, and Madame du Châtelet would have to make the best of it. Of course, Frederick's plan failed, and Voltaire was duly informed by Mirepoix of what had happened. He was naturally very angry. He had been almost induced to stay in Berlin of his own accord, and now he found that his host had been attempting, by means of treachery and intrigue, to force him to stay there whether he liked it or not. It was a long time before he forgave Frederick. But the King was most anxious to patch up the quarrel; he still could not abandon the hope of ultimately securing Voltaire; and besides, he was now possessed by another and a more immediate desire—to be allowed a glimpse of that famous and scandalous work which Voltaire kept locked in the innermost drawer of his cabinet and revealed to none but the most favoured of his intimates—La Pucelle.
Accordingly the royal letters became more frequent and more flattering than ever; the royal hand cajoled and implored. 'Ne me faites point injustice sur mon caractère; d'ailleurs il vous est permis de badiner sur mon sujet comme il vous plaira.' 'La Pucelle! La Pucelle! La Pucelle! et encore La Pucelle!' he exclaims. 'Pour l'amour de Dieu, ou plus encore pour l'amour de vous-même, envoyez-la-moi.' And at last Voltaire was softened. He sent off a few fragments of his Pucelle—just enough to whet Frederick's appetite—and he declared himself reconciled, 'Je vous ai aimé tendrement,' he wrote in March 1749; 'j'ai été fâché contre vous, je vous ai pardonné, et actuellement je vous aime à la folie.' Within a year of this date his situation had undergone a complete change. Madame du Châtelet was dead; and his position at Versailles, in spite of the friendship of Madame de Pompadour, had become almost as impossible as he had pretended it to have been in 1743. Frederick eagerly repeated his invitation; and this time Voltaire did not refuse. He was careful to make a very good bargain; obliged Frederick to pay for his journey; and arrived at Berlin in July 1750. He was given rooms in the royal palaces both at Berlin and Potsdam; he was made a Court Chamberlain, and received the Order of Merit, together with a pension of £800 a year. These arrangements caused considerable amusement in Paris; and for some days hawkers, carrying prints of Voltaire dressed in furs, and crying 'Voltaire le prussien! Six sols le fameux prussien!' were to be seen walking up and down the Quays.
The curious drama that followed, with its farcical περιπετἑια and its tragi-comic dénouement, can hardly be understood without a brief consideration of the feelings and intentions of the two chief actors in it. The position of Frederick is comparatively plain. He had now completely thrown aside the last lingering remnants of any esteem which he may once have entertained for the character of Voltaire. He frankly thought him a scoundrel. In September 1749, less than a year before Voltaire's arrival, and at the very period of Frederick's most urgent invitations, we find him using the following language in a letter to Algarotti: 'Voltaire vient de faire un tour qui est indigne.' (He had been showing to all his friends a garbled copy of one of Frederick's letters).