1,215. Donations in the Currency of the Time

Shekalim 1:4

There was also coin that was worth two sela, was called a darkon. All of these coins (in halachos 1:2-4) are the standard financial measures in Jewish law. The Rambam defines them here so that he will not have to define them every time he mentions them. [Download the Table of Talmudic Denominations]

Shekalim 1:5

The mitzvah of giving a half-shekel requires that one use the denomination that is the standard currency of the time in question, even if it is larger than the Temple shekel. One may not give less than the half-shekel that was used in the time of Moshe, which weighed 160 barley corns.