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 von List
During an 11-month period of blindness in 1902, List became increasingly interested in occultism, in particular coming under the influence of the Theosophical Society, resulting in an expansion of his Wotanic beliefs to incorporate Runology and the Armanen Futharkh. The popularity of his work among the "völkisch" and nationalist communities resulted in the establishment of a List Society in 1908; attracting significant middle and upper-class support, the Society published List's writings and included an Ariosophist inner group, the High Armanen Order, over whom List presided as Grand Master.
Through these ventures he promoted the millenarian view that modern society was degenerate, but that it would be cleansed through an apocalyptic event resulting in the establishment of a new Pan-German Empire that would embrace Wotanism. Having erroneously prophesied that this empire would be established by victory for the Central Powers in World War I, List died on a visit to Berlin in 1919.