At Salzburg, as Mozart tells Padre Martini (p. 244), a sonata was introduced between the epistle and the gospel, until Archbishop Hieronymus replaced it by a gradual in 1763.[7] Seventeen compositions by Mozart of this kind are preserved. The earliest of certain date belongs to 1775 (212 K.), and others to 1776 (241, 244, 245, 263, K.) and 1777 (274, 278, K.), but there are several almost certainly of earlier date. His sacred sonatas were performed even during his absence, according to his father (September 25, 1777). After his return, he composed three pieces of the kind, the last in March, 1780 (328, 329, 336, K.). They are all inscribed as sonatas, and all consist of a lively movement of moderate length in two parts, and in regulation sonata form. The church sonatas (sonad di chiesa) differ, indeed, from chamber sonatas (sonad di camera) in being serious, dignified, often fugued and in counterpoint, but the style has nothing in it that suggests a sacred performance. The tone is neither solemn nor devotional, nor is the style severe. The tone and treatment of the commencement remind us of the first movements of the smaller sonatas and quartets; the subjects are small, sometimes very pretty'; the treatment is free and skilful, and in the later pieces not without touches of Mozart's originality. They are usually written for two violins and violoncello, to which the organ was always added, but never {ORGAN SONATAS--NOBLE AMATEURS.} (287) obbligato nor with any regard to executive display; it has often only its customary office of accompaniment to the violoncello, in which case a figured bass part is written. Even when the organ part is independent it is for the most part limited to what the skilful organist can make out of the _continuo;_ its independence is very modest, and it never aspires to a solo or any passages. Sometimes trumpets and drums are added (263 K.) as well as oboes (278 K.) and horns (329 K.). With the extension of the orchestra the design and treatment became grander and more impressive, but still kept within comparatively narrow limits. Unhappily these organ sonatas give us not the faintest idea of Mozart's much-admired organ-playing. Not only were these compositions composed for special occasions, but all instrumental music at that time was in this sense occasional music. Orchestral compositions were, with few exceptions, written with a definite aim and under given conditions.