Schaffhausen, Stadtbibliothek, Gen. 1 is the oldest surviving copy of Adomnán of Iona's
Life of Columba, and undoubtedly its single most important witness. It was copied at Iona during (or shortly after) Adomnán's lifetime, and is also a splendid example of early medieval insular bookmaking, having been colorfully described by E. A. Lowe as embodying the "pure milk of Irish calligraphy" (CLA VII, p. xii).
St. Gall, Stiftsbibliothek, 555 contains another version of the
Life, a redaction (BHL 1887) of Adomnán's text that seems to have been made at St. Gall for the purpose of public reading. Together, therefore, these two manuscripts constitute the primary physical evidence for the
Life's origins and early circulation, its transmission to the Continent, and the Carolingian reception of St. Columba's cult.