An 11th-century certificate found in the Cairo Geniza written by a rabbinical court, testified the kosher status according to rabbinic law of the cheeses being sold by a Karaite grocer, Yefet b. Meshullam of Jerusalem. The document explains that the cheese was produced in a factory on the Mount of Olives that followed rabbinic practice. The certificate reads: The cheeses are kosher and it is appropriate for Rabbanite Jews to purchase them. We grant this permission only after having made a formal purchase from him and having witnessed an oath he took on the holy Torah. While Karaite and Rabbanite communities in this period were theologically at odds, they often maintained good social and economic relations. It was obviously as important for the Karaite grocer to do business with Rabbanite customers as it was for the latter to be able to rely on the religious acceptability of his products.