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.
Tironian notes
Tironian notes (; or Tironian shorthand) is a system of shorthand invented by Tiro (94 4 BC), Marcus Tullius Cicero's slave and personal secretary, and later his freedman. Tiro's system consisted of about 4,000 symbols that were extended in classical times to 5,000 signs. During the medieval period, Tiro's notation system was taught in European monasteries and was extended to about 13,000 signs. Tironian notes declined after 1100 but were still in some use in the 17th century, and a very few are still used today.