It was common practice in the 18th century for church music to be the medium of instruction for composers, and some remarkable compositions were brought about by this practice. Veni Sancte Spiritus (K.47) is one such piece, composed by Mozart when he was 12 years old, under the tutelage of his father Leopold. The title would suggest that it is a setting of the great Pentecost sequence, but in fact it is a setting of the second versicle of the antiphon that precedes that sequence in the Liturgy of Pentecost Sunday. The piece was originally scored for four-part choir, orchestra and organ, and was probably first performed at the Hapsburg court in Vienna in 1768, during one of many visits to that city (from Salzburg where the Mozarts lived) in which Leopold attempted to secure a royal patronage for his prodigious son. Strangely, such a patronage was never to materialize. The exchanges between solo and full choir, the imitative passagework and the exuberant Alleluia that forms a discrete second part of the composition all attest to the solid grounding the young Amadeus Mozart was given in the choral music of the churches of Salzburg at the time of Leopold Mozart and Michael Haydn.
In 1717, the theorist Johann Mattheson observed that "the most recent Italian solo concertos could be arranged for a single, polyphonic instrument such as the organ or clavier, as a curiosity." It was around this time that Sebastian Bach and his Weimar colleague Johann Walther set their hand to this very practice. The A Minor Concerto (BWV 593) is based on Vivaldi's Concerto for two violins, Opus 3 No. 8. Exploiting the possibilities for contrast inherent in the organ, Bach has deftly simulated the effect of a concerto in his transcription of this festive and lively work, with its sharp contrasts of mood and dynamic.