A treasury is either
A government department related to finance and taxation.
A place or Schatzkammer where currency or precious items (gold, diamonds, etc.) is/are kept.
The head of a treasury is typically known as a treasurer. This position may not necessarily have the final control over the actions of the treasury, particularly if they are not an elected representative.
The adjective for a treasury is normally "treasurial". The adjective "tresorial" can also be used, but this normally means pertaining to a treasurer.
As of the definition of a treasury from thêsaurus and in the context of the treasure obtained from war efforts the first recorded booty in history is a stele taken during 1160 BC.
The earliest found artefacts made of silver and gold are from Lake Varna in Bulgaria dated 4250–4000 BC, the earliest of copper are dated 9000–7000 BC.
The term treasury was first used in Classical times to describe the votive buildings erected to house gifts to the gods, such as the Siphnian Treasury in Delphi or many similar buildings erected in Olympia, Greece by competing city-states to impress others during the ancient Olympic Games. In Ancient Greece treasuries were almost always physically incorporated within religious buildings such as temples, thus making state funds sacrosanct and adding moral constraints to the penal ones to those who would have access to these funds.