The Tharisappalli Copper Plates (849 AD) are a copper-plate grant issued by the King of Venadu (Quilon), Ayyanadikal Thiruvadikal, to the Saint Thomas Christians on the Malabar Coast in the 5th regnal year of the Chera ruler Sthanu Ravi Varma. The inscription describes the gift of a plot of land to the Syrian Church at Tangasseri near Quilon (now known as Kollam), along with several rights and privileges to the Syrian Christians led by Mar Sapir Iso.
The Tharisappalli copper plates are one of the important historical inscriptions of Kerala, the date of which has been accurately determined. The grant was made in the presence of important officers of the state and the representatives of trade corporations or merchant guilds. It also throws light on the system of taxation that prevailed in early Venad, as several taxes such as a profession tax, sales tax and vehicle tax are mentioned. It also testifies to the enlightened policy of religious toleration followed by the rulers of ancient Kerala.
There are two sets of plates as part of this document, and both are incomplete. The first set documents the land while the second details the attached conditions. The signatories signed the document in the Hebrew, Pahlavi, and Kufic languages. The Tharisappalli copper plates are kept at Poolatheen Aramana (Thiruvalla) of Malankara Marthoma Syrian Church