Georg Christoph Wagenseil (1715-1777) was already active as a cpmposer under Maria Theresia's father, Karl VI. He was a pupil of Fux and the empress' teacher. In 1741 she appointed him Court Composer and teacher of her children. Since he was a keyboard virtuoso, most of his compositions are for keyboard instruments, but he also wrote a very large quantity of chamber music for various instrumental combinations and some operas and oratorios. In the Trombone Concerto, in two movements, we do not find any "baroque" turns of phrase that remind us of his teacher Fux; here we find the language of the "new music" already completly formed. Never before had anyone dared to write a concerto for the trombone, this instrument having served in the first place as a reinforcement for choirs and a filling-out of the harmony in the orchestra. The Viennese composers before Wagenseil, however, such as his teacher Fux, Biber and Schmelzer used the trombone in chamber music, often with extremely difficult solos. This concerto has been wirtten with a particularly fine feeling for nuances of instrumental tone-colour. Wagenseil displays the trombone's possibilities in every direction, exploiting its compass up to its very highest limits but placing cantabile playing in the foregound. The accompanying ensemble is based on the traditional string quintet with harpsichord, its range of tone-colours being subtly extended by means of flutes that double the violin parts and two horns.
Very little is known about the life of Matthias Georg Monn (1717-1750), who was organist at the "Karlskirche" in Vienna. In the course of his short life he wrote an amazingly large number of masses, symphonies, concertos and chamber music works. Even though he was probably the most progressive and inventive of Haydn's predeccors, one can stil hear Fux' training, especially in his fugato final movements. Monn's six string quartets, whose two-movement form (Adagio-Fugue) adheres to tradition, are probably the earliest known works for this combination of instruments. In these quartets, with their subtly worked-out dynamics (each piano, forte and crescendo is expressly stated), the four parts are treated with almost equal importance; this is all the more remarkable in view of the fact that Haydn's earliest string quartets, which were composed later, could still be regarded almost as trio sonatas with a harmonized continuo bass (which a harpsichord would not seem in the least out of place).
Florian Leopold Gassmann (1729-1774) already had an eventful life behind him when Count Durazzo (the famous champion of Gluck) introduced him to Vienna in 1763. Born in Bohemia, he  learned the violin and the harp and ran away from home at the age of about fifteen in order to study with Padre Martini in Italy. He then lived and worked in Italy as an operatic composer until he came to Vienna, where he rapidly gained high esteem. Joseph II, with whom he played chamber music several times a week, appointed him Court Conductor in 1722. Burney relates: "...This morning I went to Mr. Gassmann, Imperial Court Conductor... He aroused my greatest astonishment with a number of fugues and choruses which he showed me. They were very erudite and made in a completely individual manner. Some of them were composed in two or three different times and on two or three different subjects..." His six quartet of 1773 date from the period of his greatest fame. They are in four movements, beginning with an Adagio; the third movement is a Minuet, the two Allegros fugues, as stated in the title. These works are a unique mixture of the traditional contrapuntal style and a modern style that looks much further ahead than its own time. The Thord Quartet begins with an Adagio in which a romantic motif formed from a sixth is led sequentially through all the keys, almost as if it had started somewhere or other and would go on indefinitely. The Minuet following the first fugue is a genuine "German Dance" in Viennese style, in which the violin and the 'cello proceed in strict canon, regardless of the dissonances caused in the harmony by this mode of part-writing. We seem to hear Schubertian strains foreshadowed, while also being reminded of the canons in the Musical Offering. The fireworks of the final fugue anticipate ideas of the hundred years that are to follow.
Joseph Haydn (1732-1809) acquired his musical knowledge mainly by his own efforts. Fux' "Gradus ad Parnassum" was his main guide; the court conductor Georg Reutter and later also Porpora, Wagenseil and Glock occasionally helped him with their advice. In 1761 he came to Prince Esterhazy's court as vice-conductor. He was bound by contract "...to compose, at every command of His Serene and Princely Highness, any such music as the aforesaid Princely Highness may desire..." He spent the greater part of the year at Eisenstadt; in the winter a few months were spent in Vienna. Haydn regarded this isolation as an advantage. He wrote on one occasion: "... my Prince was pleased with all my works, I found approval, as chief of my orchestra I was able to make experiments, to observe what heightened the impression and what weakened it, in other words to correct to add, to delete, to take risks. I was cut off form the world, nobody in my vicinity could upset my self-confidence and torment me, and so I had to become original. "The Prince was an enthusiastic player of the baryton, and so Haydn had to write many works for this attractive and remarkable instrument. The Divertimento for eight instruments played here is striking in many respects, and the composer's delight in experiment can clearly be seen in it. This is already the case in the instrumentation: the baryton usually plays in octaves with one of the violins or with the 'cello; it has only a few real solos. The 'cello is almost completely independent, leaving the bass for long stretches to the violone alone, which was not usual at that time; particularly unusual, however, are the two horn parts. Horns in A are high in any case; in the solo trio of the last movement Haydn lets the first horn climb up to A"! The second horn is, on the one hand, also taken up into the highest regions; on the other, it alternates with the 'cello and violone in their bass function, this demanding the most incredible stopped notes such as did not occur before or afterwards in the music of the classical era. The entire sound-picture is thus unusual in every respect, almost extravagant if we consider further that the resonance strings of the baryton, vibrating in sympathy, spread a peculiar veiled effect over the whole.