Guidonian hand
In Medieval music, the Guidonian hand was a mnemonic device used to assist singers in learning to sight-sing. Some form of the device may have been used by Guido of Arezzo, a medieval music theorist who wrote a number of treatises, including one instructing singers in sightreading. The hand occurs in some manuscripts before Guido's time as a tool to find the semitone; it does not have the depicted form until the 12th century. Sigebertus Gemblacensis in 1105–10 did describe Guido using the joints of the hand to aid in teaching his hexachord. The Guidonian hand is closely linked with Guido's new ideas about how to learn music, including the use of hexachords, and the first known Western use of solfege.
Palaeography
The prevailing type of book-hand during what in papyrology is called the Byzantine period, that is, roughly from AD 300 to 650, is known as the biblical hand. It went back to at least the end of the 2nd century and had had originally no special connection with Christian literature. In manuscripts, whether vellum or paper, of the 4th century found in Egypt are met other forms of script, particularly a sloping, rather inelegant hand derived from the literary hand of the 3rd century, which persisted to at least the 5th century; but the three great early codices of the Bible are all written in uncials of the biblical type. In the Vaticanus, placed in the 4th century, the characteristics of the hand are least strongly marked; the letters have the forms characteristic of the type but without the heavy appearance of later manuscripts, and the general impression is one of greater roundness. In the Sinaiticus, which is not much later, the letters are larger and more heavily made; and in the Alexandrinus (5th century) a later development is seen, with emphatic distinction of thick and thin strokes. By the 6th century, alike in vellum and in papyrus manuscripts, the heaviness had become very marked, though the hand still retained, in its best examples, a handsome appearance; but after this it steadily deteriorated, becoming ever more mechanical and artificial. The thick strokes grew heavier; the cross strokes of T and Θ and the base of Δ were furnished with drooping spurs. The hand, which is often singularly ugly, passed through various modifications, now sloping, now upright, though it is not certain that these variations were really successive rather than concurrent. A different type of uncials, derived from the Chancery hand and seen in two papyrus examples of the Festal letters despatched annually by the Patriarch of Alexandria, was occasionally used, the best known example being the Codex Marchalianus (6th or 7th century). A combination of this hand with the other type is also known.