296 The oldest copy of them dates from circ. 1720; they belong therefore to the late Cöthen period. The 1720 MS. is in A. M. Bach’s handwriting and was discovered in 1814 at Petrograd among old papers about to be sent away to a butter dealer. The Sonatas are in P. bk. 228. 297 They also date from the Cöthen period and are in P. bk. 238a, 238b. 298 Forkel omits to mention the Brandenburg Concertos (P. bks. 261-266); the Overtures in C major (P. bk. 267), B minor (P. bk. 268), D major (P. bk. 269), D major (P. bk. 2068); and the Violin Concertos in A minor (P. bk. 229), E major (P. bk. 230), and (for two Violins) in D minor (P. bk. 231). In B.G. XXI. (1) is a Symphonic movement, in D major, for Violin and orchestra. A Sinfonia in F major (B.G. XXXI. 96) is another version of the first Brandenburg Concerto. The Clavier Concertos have been mentioned supra. 299 The set of five is complete only for Christmas Day, Feast of the Circumcision, Whitsunday (one of the five is of doubtful authenticity), Purification of the B.V.M., and Feast of St. Michael the Archangel. See Terry, _Bach’s Chorals,_ Part II. 2 ff. 300 In giving the number of _Passions_ as five, Forkel repeats the statement of the _Nekrolog._ The number corresponds with the five sets of Church Cantatas which Bach is known to have written. It is, however, exceedingly doubtful whether Bach wrote more than four _Passions._ Only those according to St. Matthew and St. John have come down to us from C. P. E. Bach, who was left the Autographs of both by his father. The _St. John Passion_ was first performed in 1724 and the _St. Matthew Passion_ in 1729. Picander, Bach’s librettist, certainly wrote two other Passion texts, one of which was written for Good Friday 1725, and the second, based on St. Mark’s Gospel, was actually performed at St. Thomas’, Leipzig, on Good Friday 1731. Spitta (ii. 505) gives good reason to hold that Bach’s music for this Passion was adapted from the _Trauer-Ode,_ which he had written in 1727 in memory of Queen Christiane Eberhardine. But of the 1725 _Passion_ there is no trace. If it ever existed, its loss probably may be assigned to Wilhelm Friedemann’s carelessness, to whom presumably it was assigned in the division of Bach’s property after his death. But even so, we have no more than four _Passions._ There exists, however, a fifth _Passion according to St. Luke,_ which is undoubtedly in Bach’s Autograph, and which Spitta is inclined to attribute to Bach himself. It is published by Breitkopf and Haertel, but is generally regarded as being by another composer than Bach, who probably copied it for use at Leipzig. On the whole matter see Spitta, ii. 504 ff., Schweitzer, chap. xxvi., and the Bach-Jahrbuch for 1911