The manuscript is a copy of a letter in Wagnière’s hand. Apart from proclaiming his love and loyalty to the sovereign of Prussia, Voltaire alludes to the Battle of Rossbach where Frederick the Great, king of Prussia, faced an Allied army led by Monsieur de Soubise (Charles de Rohan Soubise). Voltaire likens the military prowess of the monarch to that of Charles XII of Sweden and attests to an unending French admiration and respect for the king of Prussia. The incipit of the MS4 slightly differs from the one found in the EE, with the latter reading ‘Ne vous effraiez pas d’une lettre qui peutêtre sera longue, qui est la seule chose qui puisse’. Additionally, this letter is placed in September or October 1757 in the various manuscripts and editions; it is a reply to D7373, and was written before Voltaire knew that Frederick had been obliged to give up hope for the time being of a pitched battle against Soubise; but the exact date is difficult to fix, for when the king arrived at Erfurt 14 September, his forces were so reduced (13,000 against the 56,000 of the allies) that a battle would have been madness; yet he remained there until the 28th, the allies timorously fearing to attack, Frederick playing with the idea of suicide before he finally resigned himself to the loss of east Prussia; taking all these facts into account, Voltaire’s letter may be dated as above, with a possibility of error of not more than two or three days either way.