A medieval codex originally copied at Reichenau circa 1250, and preserved at Fulda, titled
Abbreviatura, Hermann Contractus is an index key to some of the abbreviations that medieval writers used in order to save space when writing on expensive parchment. Fulda MS 100 C 4, consisting of 12 pages of abbreviations and their meanings, is attributed to the Benedictine monk and scholar
Hermann of Reichenau, who lived from 1013-1054. Its digital facsimile is available from the Fuldaer Digitale Sammlungen
at this link.
This reference I obtained from
Roger Pearse's blog received on October 3, 2020.
This is the third page opening of the Abbreviatura at Fulda.