The Contract of Ardra was a contract between the Ventaxians and Ardra, a mythical being in Ventaxian theology, in the 14th century. In reality, the agreement was created by Ventaxian leaders at the time to convince their people to stop fighting.
The Contract detailed an agreement in which Ardra promised the Ventaxians one thousand years of peace and prosperity in return that, at the end of that time, they would become her slaves. The Contract also specified the date when it comes to term, as well as that there would be tremors and visions leading up to that date. It stated that Ardra would effect these changes and that would provide evidence of her identity.
The contract was written on scrolls and kept in the Atheneum vaults. Ventaxian theologians would study the scrolls for centuries afterwards.
When an impostor attempted to collect on Ardra's behalf in 2367, her legitimacy was questioned by the crew of the USS Enterprise-D. They successfully proved their case and the contract was officially dissolved during an arbitration conducted by Data. (TNG: "Devil's Due")