1,214. The Value of Various Currencies in Halacha
Shekalim 1:2
The amounts mentioned in the Torah for fines to be paid by rapists, seducers, slanderers or for the death of a servant are all in shekalim, a denomination of silver coin weighing 320 barley corns. The Sages increased the value of a shekel, making it equal to a sela, which was a coin of the Second Temple period. A sela was a silver coin weighing 384 barley corns.
Shekalim 1:3
A sela is four dinar; a dinar is six maah; a maah was called a geira in the time of Moshe. A maah is equal to two pundion, and a pundion is equal to two isar. A prutah is one-eighth of an isar. Therefore, the weight of a maah/geira is 16 barley corns, an isar is four barley corns and a prutah is half a barley corn.