The manuscript is a draft of a letter contemplating ‘Rêve’ (Œuvres de Frédéric, xv.29–34), composed by Frederick II, King of Prussia, and dispatched to Voltaire. It also references the poetry authored by Frederick II, as showcased in D20721, and cites the previous letter, which had solicited the king’s contribution to the Bern prize. T. D. N. Besterman traditionally placed this letter in August 1777; however, since it responds to the king’s letter of 9 July (D20721) and was answered by Frederick on 13 August (D20764), a safe estimation places its composition around 25 July 1777.