Counterpoint in Jérôme Joseph de Momigy’s article “Sonate” for the musical section of the Encyclopédie méthodique (1818) The article “Sonate” of the musical section of the Encyclopédie méthodique (1818), written by Jérôme Joseph de Momigny, provides most interesting insights on the musical writing and of the role of counterpoint within this major genre. Within a history of the genre, the text allows its author to comment on the learned instrumental style of J. S. Bach as perceived by a learned musician of his time. With the help of detailed analyses of works by Haydn, Mozart, Dussek, Steibelt and Beethoven, Momigny establishes his own personal Pantheon, of which emerges the unequaled figure of Haydn. The criterion of evaluation is none other than the presence of strict style and the skill of its usage in the sonata. In an attempt to stigmatize the aesthetic thought of Jean-Jacques Rousseau, Momigny comes close to his notion of “unite de mélodie”, melodic unit, to explain the value of Haydn’s counterpoint. The contemporaries, among whom Beethoven, are reproached their writing faults. Obsessed by the conservation of the rules of strict style, Momigny refuses to read modern sonatas according to new instrumental criteria. At the same time, he is in this article one of the firsts in France to postulate the existence of a Viennese school, yardstick for the evaluation of other composers. This choice, later relayed by the musicological discourse, turned to a disadvantage for composers which remain today unknown outside a circle of specialists.