CLAVIUS, Christophorus. Computus ecclesiasticus per digitorum articulos, & tabulas traditus. 1603.

Rome, Zannettum, 1603.

16mo (154x87 mm), 107-(20)-(1bl.) pages.  binding : Old full vellum. Spine a little chipped. 

references: The Erwin Tomash Library on the History of Computing [ C97 (this copy) : "Computus ecclesiasticus was not directed to the subject of calendar reform but to the calculation of the dates of the Christian festivals, chiefly Easter. As implied by the title, Clavius explains two ways of performing the calculations, one using the fingers and another by means of the extensive set of tables included in the work. The text contains no diagrams of the finger methods.".

provenance: Erwin Tomash (with is label). One of the most important library on the history of computing.

Price : 1200 €