This is the first comprehensive study of an ingenious number-notation from the Middle Ages that was devised by monks and mainly used in monasteries. A simple notation for representing any number up to 99 by a single cipher, somehow related to an ancient Greek shorthand, first appeared in early-13th-century England, brought from Athens by an English monk. A second, more useful version, due to Cistercian monks, is first attested in the late 13th century in what is today the border country between Belgium and France: with this any number up to 9999 can be represented by a single cipher. The ciphers were used in scriptoria - for the foliation of manuscripts, for writing year-numbers, preparing indexes and concordances, numbering sermons and the like, and outside the scriptoria - for marking the scales on an astronomical instrument, writing year-numbers in astronomical tables, and for incising volumes on wine-barrels. Related notations were used in medieval and Renaissance shorthands and coded scripts. This richly-illustrated book surveys the medieval manuscripts and Renaissance books in which the ciphers occur, and takes a close look at an intriguing astrolabe from 14th-century Picardy marked with ciphers. With Indices. "Mit Kings luzider Beschreibung und Bewertung der einzelnen Funde und ihrer Beziehungen wird zugleich die Forschungsgeschichte - die bis dato durch Widerspruechlichkeit und Diskontinuit�t gepr�gt ist - umfassend aufgearbeitet." Zeitschrift fuer Germanistik.

Two remarkable Iranian world-maps were discovered in 1989 and 1995. Both are made of brass and date from 17th-century Iran. Mecca is at the centre and a highly sophisticated longitude and latitude grid enables the user to determine the direction and distance to Mecca for anywhere in the world between Andalusia and China. Prior to the discovery of these maps it was thought that such cartographic grids were conceived in Europe ca. 1910. This richly-illustrated book presents an overview of the ways in which Muslims over the centuries have determined the sacred direction towards Mecca (qibla) and then describes the two world-maps in detail. The author shows that the geographical data derives from a 15th-century Central Asian source and that the mathematics underlying the grid was developed in 9th-century Baghdad.