The well-known fragment of a musical score of a chorus from Euripides' Orestes, published in 1892 by K. Wessely was dated by its first editor to the first century after Christ. Wessely, who had no dated palaeographical material for comparison, based his dating on external factors. ‘The scrap was taken (presumably when unpacked in Vienna, though this is not specifically mentioned) from a layer of papyri which belong to the first century A.D. (the Hadrianic period at the latest), a judgement that I can confirm by means of the dates on some of the pieces should the letter forms not be thought sufficient indication.’ Allowing for a certain period of years to elapse before a literary work was set aside, Wessely concluded that ‘the evidence permits a date in the time of Augustus’. This conclusion seemed to gain force from a suggestion that the papyrus was contemporary with Dionysius of Halicarnassus' musical score of the Orestes (de comp. verb. 11), and has been generally accepted. Nevertheless, the dating is at least two centuries too late. The character of the hand is to a large extent concealed by the photograph (and subsequently apparently it has always been this reproduction that has been reproduced) which accompanied the editio princeps. Seen in the original, however, as I was privileged to see it in the summer of 1955, its unmistakable Ptolemaic character thrusts itself on the attention. The mere size of the letters, especially their width, the coarse cut of the writer's pen which can only make thick strokes, the unnecessary horizontal link-strokes found at the top of a vertical hasta (seen clearly in the μ of μέγας, l. 2) are among such unmistakable stylistic features. Moreover, some of the letters have a characteristic Ptolemaic shape—α, κ, λ, χ, and above all τ, which begins with a bold initial upstroke on the left, υ which has a long, shallow bowl and a leftward curve at the foot of its vertical; to which one is tempted to add the archaic square ε of the musical notation. Among examples of Ptolemaic calligraphy this hand must take a high place. I know of no precisely similar dated handwriting, for dated literary hands of this period are still rare. But a number of similarities can be seen in any one of the following non-literary texts: P. Cairo Zeno 59532 (epitaph) and 59533 (music), and P.S.I. 379 (letter of 249/8 B.C.), all from the Zenon archive and to be dated about 250 B.C.; P. Teb. 811, a smaller and rougher hand of 165 B.C.; P. London 44, a good documentary hand of 161 B.C. which I should judge later than the Orestes. 260 B.C. and 150 B.C. are the extreme limits between which I would assign the date of this papyrus, with a preference for about 200 B.C. On this revised view of its dating, the Orestes fragment is even on external grounds to be reckoned among the oldest surviving pieces of Greek music, only the Zenon scrap (P. Cairo Zenon 59533) being perhaps older.