«Simple», I reply, «Monotheism. The single God, Ahura Mazda in combat with Ahriman, the Lie. And three simple tenets: Humata, Hukta, Huvareshta “good thoughts, good words, good deeds”, sometimes translated by the venal as good eggs, good fish, good meat!»
He is impressed. He tells me that he was even more impressed with the musical works of a Parsi composer called Kaikushru Sorabji  who wrote an interminable piece for piano which was performed but once by a friend of his, the famous pianist John Ogdon. Sorabji had arrived in England as a convert to Christianity but reverted to Zoroastrianism later.
Other party guests now joined in and someone inevitably mentioned Zubin Mehta and then Freddie Mercury whose interpretation of our three tenets was probably somewhat different. Three Musical Parsis. (The title of my next opera!)
Grandson noted that Parsis were a tiny and dwindling minority in India but had influenced it in a disproportionate way.
«Like the Jews»,
«No, unlike the Jews», said Grandson. «Parsis exude no sense of victimisation.»
«Quite right», I say, «We eat what we like and so don’t feel sorry for ourselves. Pork, beef, no taboos. There was the news recently of a Parsi wedding serving vegetarian food. Which is like a Wordsworth poem with every reference to flora removed.»
Now the dinner guests in remote Exmoor, like those at the feast attended by the Ancient Mariner, had never been to a Parsi wedding. They did not know of what I spoke and if I had said Bheeda Pareeda or Patra-ni-Machhi they may have thought I was announcing the names of famous Parsi sopranos.
I was then pressed for a brief history of Parsis and I rehearsed the glories of the Achaemenid Empire, overrun eventually by the Macedonian bandit, Alexander the Damned. I progressed to the Sassanians who were in the 7th century AD overthrown by Arab-Muslim occupation, which caused our ancestors to flee as refugees to India.
«I’d like to convert to Zorastrianism», says Grandson.
«Feel free», I say, «But we Parsis won’t accept you as one of us. You have to be born of a Parsi father to claim that distinction.»
«So no converts?»
«No. That’s why we are an endangered species. The silence will soon descend.»
A bit melodramatic, but it had its effect. A silence descended as the gooseberry tart was being served.
«So you seem… er… content to die out?»
«Of course not», I reply. «We have stuck to racial purity in the interests of keeping the relative wealth of the Parsi community within itself. The only concession we have made through the ages is allowing the progeny of Parsi fathers who have made children with non-Parsi servant girls to join the fold.
«Now this is unfortunate as, for instance, my sister’s children, very beautiful human beings, can’t be included as their father was Hindu — not that it seems to bother them: they view Parsis and our ways with an amused tolerance. The in-breeding has diluted the gene-pool and we are sort of funny. And even if we resemble them we shouldn’t go the way of the Dodo!»
«So what’s to be done?»
«Well, we have vast pockets of invested wealth. The lands in Mumbai which contains the towers from which dead bodies are disposed by feeding them to the vultures, are a very expensive chunk of real estate. The vultures are dying out as they absorb Diclofenac through eating cattle carcasses. It’s a medicine for cattle but lethal to the birds and has killed 95% of Indian vultures. We should dispose of the dead differently — after all the Zoroastrian Kings, Cyrus and Darius, are buried in tombs. The plan is we sell off the land and hold the proceeds in a Parsi Survival Fund.
«Then use the fund to import a quarter of a million volunteer women of child-bearing age from countries such as Russia, Romania and places from which adventurous or desperate women volunteer for questionable service in the Gulf and even come to India to join Bollywood dancing choruses and work in the sex trade. These young ladies would be given the status and lifestyle of memsahibs and be required to, with forms of easy social introduction, provide the next generation of Parsis. As Parsi Baby-mothers they would be pampered and pensioned as saviours of the race.»
«I think I approve», says the late great writer’s Grandson. Sorabovsky, Mehtanov or Mercurevich, anyone?