Long before the foundation of the Musica Viva Society in 1945, Sydney had been served by a succession of active chamber music ensembles and organisations. At the turn of the twentieth century, the Sydney Morning Herald reported on the existence of several, with an opening qualification:
Quartet societies have never maintained any lengthy permanence in Sydney. The Zerbini string quartet (headed by the famous viola player of that name) became an established institution; the Mendelssohn Quintet Club lasted for some time. Mr Rivers Allpress and Miss Lottie Hyam sustained the appreciation of this form of composition, and M.F. Aengenheyster conducted the Pleyel classical concerts (leader M. Henri Staell) for several years. The Orpheus Club for a number of years included quartets and quintets in its miscellaneous programmes. 
In 1909, the Austral String Quartet was formed under the leadership of violinist Cyril Monk. It was only to remain active until around 1916, though it included among its later members the composer Alfred Hill and the young Sydney-born, German-trained cellist Carl Gotsch.
Gotsch's father, Herr Carl Gotsch, had been active since the early 1880s, as a music teacher in Woolloomooloo and Darlinghurst, and as a presenter of zither orchestra concerts. Carl Gotsch junior and his sister Leonore, a soprano who had also trained in Germany, began to appear regularly in Sydney concerts in 1911. After World War I, however, Carl junior spent the next 15 years in Indonesia. He returned to Sydney in 1934, and in December 1937, at the Little Theatre in Phillip Street, conducted a staged production of Hindemith's children's ballet-operetta Tuttifaentchen (The Living Marionette), choreographed by Moya Beaver and with the young Marea Wolkowsky (Maria Prerauer) in the singing role of Trudel.
The following Christmas, 1938, the Hindemith production was remounted under the banner of Gotsch's recently-formed Collegium Musicum, at the larger St James Theatre, with a cast including radio celebrity Nigel Lovell. During its second year, 1939, the Collegium's activities included an ABC national broadcast of its performance of Bach's Coffee Cantata. Other founder members of the group included Gotsch's sister Leonore, amateur cellist Edward Marriott and early-music specialist and recorder player Lucas Staehelin. Informally constituted at first, the group operated out of Gotsch's teaching studio in an old building, a well-known Bohemian haunt, in Hamilton Street, just off Hunter Street, in the city. The studio also served as venue for the group's long-running fortnightly Friday lunchtime concerts. According to the Bulletin:
No group in Sydney was responsible for a more vital atmosphere than the Sydney Collegium Musicum, in the period prior to World War II. Up the rickety staircase in Hamilton Street was a room festooned with batik and scattered with objet d'art from Java [...] and in this room the best and most dedicated players in Sydney gave lunch-hour recitals the memory of which brings a warm glow to those who experienced them. 
The Collegium was especially notable for its pioneering performances of both 'Ultra Modern' chamber music (as the program for a concert broadcast on ABC Radio 2BL on 23 October 1936 was described) and early music. Flautist Neville Amadio recalled first Australian performances of Hindemith's Funeral Music for George V and Britten's Simply Symphony on the one hand, and of Bach cantatas on the other. Other young Sydneysiders, later well known, who played in Collegium concerts included pianist Maureen Jones, violinist Ernest Llewellyn, cellist Nelson Cooke, and oboist Charles Mackerras, who later also conducted at least one Collegium performance on 15 April 1945.
From records of the group's radio broadcasts for 2BL and 2FC in the late 1930s, Donald Westlake compiled a list of 48 works by such modern European composers as Hindemith, Bartók, Szymanowski, Casella, Milhaud, Reger, Roussel, Schoenberg, Zemlinsky, Delius, and Goossens. Locally active composers whose works featured in seasons included Stanley Bate, whose ballet score Perseus was played in 1940, and the Spanish priest-composer Joseph Muset, who was director of music at St Patrick's College, Manly, during World War II.
Despite the establishment of the Musica Viva Society, a rival chamber music organisation which lured away much of the younger musical talent, founded by former Collegium viola-player Richard Goldner in 1945, the Collegium Musicum continued to present regular concerts until 1950, when it was reported that Gotsch was taking a break to go abroad.