Syria belonged to the Roman Empire from 64 BC, when it was annexed by Pompey, until 135 AD. It was home to two of the greatest mints of the Roman Empire: Antioch and Tyre. Syrian mints produced many of the coins mentioned in the Bible, such as tetradrachms and Tyrian shekels.
Tyrian shekels were used to pay the Temple tax during the Roman Empire. Every year, Jewish men who were 20 years of age or older had to pay a half shekel Temple Tax. Genesis mentions the Tyrian shekel several times. When Sarah died, Abraham wanted to bury her. In order to do so, he had to buy a cave from Ephron, who said:
“My lord, hearken unto me: the land is worth four hundred shekels of silver; what is that betwixt me and thee? Bury therefore thy dead.” And Abraham hearkened unto Ephron; and Abraham weighed to Ephron the silver, which he had named in the audience of the sons of Heth, four hundred shekels of silver, current money with the merchant (Gen 23: 15-16).
Tetradrachms were silver coins that weighed 14 or 15 g. These coins, minted in Antioch, Tyre and a few other minor mints supplied all of Syria. But Antiochene and Tyrian tetradrachms circulated on very different territories of this provice, and had their own particular characteristics.
Nero was responsible for several changes on the silver coinage. Tyre ceased to produce silver coins, so Antiochene tetradrachms dominated the whole region. All the coins issued before Nero were removed from circulation. This process took several years. Nero is also responsible for standardizing the tetradrachm coinage: one tetradrachm was worth four denarii (before him, three denarii tetradrachms circulated too).
Since Tyran silver coins were almost pure silver bullion, and the reverse used to be a standing eagle, when they went out of circulation, Antiochene tetradrachms started to show a new reverse: an eagle with its wings spread. Butcher and Ponting in their article “The Silver Coinage of Roman Syria Under the Julio-Claudian Emperors” say that “the new Neronian coins effectively bore a ‘Tyrian’ type to announce that they were ‘good silver of the Tyrian stamp’”, which seems to be the main reason to change their reverse.
Syrian coins, both from Tyre and Antioch can still be found today. Check out some related coins on VCoins.
K. Butcher and M. Ponting, ‘The Silver Coinage of Roman Syria Under the Julio-Claudian Emperors’, LEVANT 41 (2009), 59-78