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.
Guido of Pisa
Guido of Pisa (died 9 July 1169) was a geographer from Pisa. In 1119 he edited and updated the "Geographica", a geographic encyclopedia first created in the eighth century by Anonymous of Ravenna. It followed in the tradition of earlier geographies, such as Strabo's Geographica, Pomponius Mela's "De situ orbis", Claudius Ptolemy's Geographia, and the Antonine Itinerary. Guido's book included text, as well as maps of Italy and the world as it was known to the Romans. It also included the only known text of the "Carmen in victoriam Pisanorum". His map of the Western Roman Empire contains the inscription "Carantano", which is probably the first cartographical mention of the Slovene territory.