In the history of seventeenth-century European music the court of Christian IV (r. 1588-1648) occupies a position of prominence. Christian, eager for fame as a patron of the arts, drew to Denmark many of the musical giants of the age, among them the lutenist John Dowland and the composer Heinrich Schltz. Sadly, except for financial records and occasional letters still in the archives, few traces remain of these brilliant years in Denmark. The music composed and played during this half century has largely disappeared, most of it probably in the tragic fire of 1794 that destroyed the old Christiansborg Castle in Copenhagen and with it the court music archives. Except for the recently-discovered Clausholm Fragments, only three specimens of keyboard music from the period remain: Ny kgl. Saml. 1997 fol. (Obmaus Tablature), Gl. kgl. Saonl. 376 fol. (Copenhagen Tablature), and mu 6703.2131/6 (VoigtlaJnder Tablature). It has generally been assumed that the manuscripts were of German origin. The present study, however, demonstrates a probable Danish origin for the third, possible Danish connections for the second, and establishes that the first is of Austrian provenance. The Obmaus Tablature is an amateur's preservation of a German keyboard style already outdated. This slender manuscript, dated 1637, contains a total of ten "archaic" pieces exhibiting the peculiarities of keyboard dances and song settings from the late sixteenth century. The awkward style of the pieces leads to the conclusion that they were transcribed for keyboard--more literally than imaginatively--from lute originals. The Copenhagen Tablature, consisting of thirty-four folios, is of primary importance for its evidence of the spread of the French claveqin style and the development of the keyboard suite. Of the sixty-nine pieces the majority are French dance forms, several with doubles; also included are preludes, German dances, and settings of chorales, psalms, and secular songs. In this study the dating of the various portions of the manuscript is discussed, and conjectures as to the compilers are presented.