Johann Gottlieb Janitsch was born on 19 June 1708 in Schweidnitz, Lower Silesia (today Poland). After studying jurisprudence as well as gaining musical proficiency in various places, he was appointed musician at the Berlin court of Frederick the Great in 1740, where he enjoyed considerable success until his death in 1762. Thus it is not surprising that all three sources of the Quartet op. 5 in D major are in Berlin, where they are kept by the Berlin State Library, Prussian Cultural Heritage Foundation. All three are apograph copies of the parts without a score, containing some errors and in general inconsistent: A. Mus. ms. 11103/24 has an old possessor’s entry “N° 49 | Krämer | 21.”, referring to the Berlin banker Johann Sigmund Krämer: Echo. | 1914.56.0 | D:# major | N: 58 [...] | Suonata. da Camera: | a 4: Strom: | [Incipit] |Flauto Traverso | Oboe. overo Violino | Viola di Braccio | e | Cembalo: con Violoncello. | Dell Sigr: Janitsch: | Opera Vta. The end of the continuo part is dated 30.11.57, which could mean February or November. B. The manuscript SA 3152 used to belong to the harpsichordist Sara Levy (1761–1854), who bequeathed her extensive collection to the Sing-Akademie. The set of parts is similar to the first source and perhaps a copy thereof: Echo: | Sonata da Camera 25. in D. # | à 4tuor | [Incipit] |Flauto Trav: | Violino | Viola da Braccio | Basso Continuo e Violoncello | Dell S: Janitsch | Opera Vta. The single parts are labelled “Flauto Trav:”, “Flauto Secondo ô Violino o Violino Pomposo”, “Viola di Gamba overo Viola di Braccio” and “Basso e Cembalo”. C. SA 3164 once belonged to Johann Rudolf Siegmar Printz (fl. 1766-1783), the bassoonist of the Prussian Court Orchestra. This copy, which also belongs to the Sing-Akademie, is often more precise than the first two sources, especially regarding the figured bass, but phrasing marks are almost completely lacking. Sonata da Camera | a 4tro | Oboe Flauto Traverso | Violetta | e | Basso | di Sigr: Janitsch. No: 18 Here the parts are marked “Flauto Traverso”, “Oboe”, “Violetta” und “Basso e Cembalo”. The different instruments named by the sources allow for a variety of performance possibilities: only the upper part is allotted to the transverse flute alone. The second part can be performed by an oboe, a second flute, a violin or violino pomposo, the third by viola, viola da gamba or violetta, and the bass by a harpsichord and a cello or another bass instrument. (Indeed, the source that belonged to the bassoonist does not mention a violoncello, but only a “bass and harpsichord”.) The first two sources allow for a bit of polyphony in the third movement by the two middle voices. Of course, double stops can be realized only by string instruments; other instruments may simply omit the lower part. Concerning the instruments: in 1782 Johann Samuel Petri described the violino pomposo as a violin “the size of a viola with five strings, thus acting concomitantly like a viola and a violin.” By contrast, the violetta is often equated with the viola, but Friedrich Erhard Niedt asserted in 1706 that the violetta is “a discant viola da gamba”, “also an alto viola da gamba”, but he revised the edition 1721 to say that the “Violetta is a violin for the middle part, executed on violas or on small viols.” Therefore the third part is for viola or viol, probably meaning an alto or a tenor viol. In addition to the common embellishments (Ÿ and m) one finds in the sources A and B a turn (T) in conjunction with m, as well as wavy lines to indicate a bow tremolo in the viola or viol part. The new edition is based primarily on source A, but source C was often consulted and sometimes respected, especially for the figured bass. The difference between dots and vertical lines as accents is often unclear or inconsistent in the sources. Flaws in the musical text were corrected and phrasings cautiously adjusted based upon parallel passages. Harry Joelson