The Temple tax was a tax which went towards the upkeep of the Jewish Temple, as reported in the Mishna and New Testament, and based on an interpretation of Exodus 30:13.
In later centuries, the half-shekel was adopted as the amount of the Temple Tax, although in Nehemiah 10:33–34 the tax is given as a third of a shekel.
Exodus 30:13 This is what each one who is registered shall give: half a shekel according to the shekel of the sanctuary (the shekel is twenty gerahs), half a shekel as an offering to the Lord. NRSV
After the return under Nehemiah, Jews in the Diaspora continued to pay the Temple tax. Josephus reports that at the end of the 30s CE "many tens of thousands" of Babylonian Jews guarded the convoy taking the tax to Jerusalem (Ant. 18.313).
The tax is mentioned in the Gospel of Matthew in the New Testament, when Jesus and his disciples were in Capernaum. The collectors of the temple tax (Greek: διδραχμα, didrachma) came to Peter and said "Does your teacher not pay the temple tax?" The narrative, which does not appear in the other gospels, leads to a discussion between Jesus and Peter about payment of the taxes levied by the "kings of the earth", and the miracle according to which Peter finds a stater (Greek: στατηρα), in the mouth of a fish, which is used to pay the tax due for both of them. The stater "was reckoned as equal to four drachmæ, and would therefore pay the didrachma both for Peter and his Master".