R - Metropolitan Museum of Art

66-74. Glass served a fiducial function in
the Islamic world, primarily in the Egyptian
monetary system between the eighth
and the fifteenth century. The coins of
gold (dinar), silver (dirham), and copper
(fals) that were in circulation during the
twelve hundred years under discussion in
this publication were handcrafted and,
unlike our modern machine-made coinage,
did not have a precisely calibrated
weight. Thus, a simple payment in
coins for an item of a stated price was
not possible.
To remedy this problem, a system was
devised utilizin glass weights that were
the precise equivalents (or fractions or
multiples) of the standard unit weights of
the three denominations of coins. When
a business transaction was carried out,
coins were weighed in bulk against glass
weights equaling the price of the purchase.
In Early Medieval business documents
the Arabic verb wazana (to weigh)
was used for any transaction in which
money changed hands. The issuing of
weights was carefully regulated and was
generally delegated by the caliph to the
governor or viceroy, when one existed;
to the finance director; or to both.
The eight coin weights illustrated here,
which represent only a fraction of the
Metropolitan's collection of these fiducial
tools, range from a very precisely identified
one-dinar weight (green, at the
center foreground, no. 66) issued by
al-Qasim ibn 'Ubayd Allah, who was finance
director in Egypt from 734 to 742,
to the Mamluk one-half-dirham weight
(aubergine and opaque white, at the bottom
right, no. 73) with an unintelligible
Arabic inscription.
Another type of weight, known as a
ring weight (top left, no. 74), was used for
weighing meat, grapes, and other commodities.
While approximately ten thousand
coin weights are extant in public
and private collections here and abroad,
complete examples of the larger ring
weights-equaling a rati (a unit of
weight), its double, or its fractionsnumber
less than one hundred. Such
objects are usually found in fragmentary
condition because when a new governor,
viceroy, or finance director was appointed,
weights were issued in the new
appointee's name and old weights were
ordered destroyed.
66-74
53