The phrase "al pi Kabalah" (based on Kabalah) is often used in teshuvot for various minhagim or halachot.
When is the first recorded instance of somebody recording the Halacha either "al pi Kabalah" or by quoting the Zohar? To clarify, I want to know the Year. It does not matter if they were a major posek or not, just as long a they were mentioning practical rather than theoretical halacha. If they are quoting the zohar they have to mention it by name.