a pen. In cutting a hard surface, it is easier to form angles than curves; in writing the reverse is the case; hence the development of writing was from angular letters ("capitals") inherited from epigraphic style to rounded ones ("uncials"). But only certain letters were affected by this development, in particular E (uncial ε), Σ (c), Ω (ω), and to a lesser extent A (α). Ptolemaic period The earliest Greek papyrus yet discovered is probably that containing the Persae of Timotheus, which dates from the second half of the 4th century BC and its script has a curiously archaic appearance. E, Σ, and Ω have the capital form, and apart from these test letters the general effect is one of stiffness and angularity. More striking is the hand of the earliest dated papyrus, a contract of 311 BC. Written with more ease and elegance, it shows little trace of any development towards a truly cursive style; the letters are not linked, and though the uncial c is used throughout, E and Ω have the capital forms. A similar impression is made by the few other papyri, chiefly literary, dating from about 300 BC; E may be slightly rounded, Ω approach the uncial form, and the angular Σ occurs as a letter only in the Timotheus papyrus, though it survived longer as a numeral (= 200), but the hands hardly suggest that for at least a century and a half the art of writing on papyrus had been well established. Yet before the middle of the 3rd century BC, one finds both a practised book-hand and a developed and often remarkably handsome cursive. These facts may be due to accident, the few early papyri happening to represent an archaic style which had survived along with a more advanced one; but it is likely that there was a rapid development at this period, due partly to the opening of Egypt, with its supplies of papyri, and still more to the establishment of the great Alexandrian Library, which systematically copied literary and scientific works, and to the multifarious activities of Hellenistic bureaucracy. From here onward, the two types of script were sufficiently distinct (though each influenced the other) to require separate treatment. Some literary papyri, like the roll containing Aristotle's Constitution of Athens, were written in cursive hands, and, conversely, the book-hand was occasionally used for documents. Since the scribe did not date