Indian copper plate inscriptions
Indian copper plate inscriptions are legal records engraved on copper plates. The practice was widespread and long-running in the Indian subcontinent; it may date back to as early as the 3rd millennium BCE, however the vast majority of recovered plates were produced in the 1st millennium CE. The plates were legal documents which registered and recorded an act of endowment, i.e.
Source: Wikipedia — Indian copper plate inscriptions (CC BY-SA 4.0)