Buddhists and Christians Together (for Dinner at Least)
A Buddhologist colleague once mentioned that she'd heard a colleague point out (yes, this is third hand) that you could see the Protestant origin of Religious Studies in its focus on doctrines as the center of religion. But if Religious Studies had started in Judaism or Hinduism, on the other hand, the person said, you'd see that food practices are really the center of religion.
I was reminded of that in my summer trip to Russia. In an interview with the Khambo Lama or abbot of the newly revived Aga datsang (monastery) -- that's a picture there -- he told me a funny story about the recent Congress of World Religions in Moscow this summer (details here and here). The Jews could only eat kosher, and the Muslims could only eat halal. So the result was only the Christians and the Buddhists could eat together! (He didn't mention the Hindus, but they have their own purity regulations and rules -- no beef, certainly.)
Actually Buddhism and Christianity have this similarity: they are both explicitly multi-ethnic religions, whose early writings expressly attack the purity legislation, food laws, and ethnic exclusiveness of their ethnic parent religion -- Hinduism and Judaism respectively.
In fact, one could argue that Christianity and Buddhism are the only well-established really multi-ethnic religions in the world. Virtually all the other religions of the world are for one ethnic group alone.
And what about Islam? That's a fascinating case. I think you could argue that while Islam accepts adherents from every ethnic group, it follows the American ideal of a melting pot: e pluribus unum ("from many, one"). I've touched on this before (see here). Traditionally, this was a purely eschatalogical ambition, but this aim of absolute cultural unity of the Islamic world is getting a lot more traction lately (see here).
Not eating together can strike people as very offensive. Qubilai Khan (a.k.a. Kubla, Kublai) in 1280 invited some Muslim merchants to his palace but they demurred and would not eat his meat, because it was slaughtered in the Mongol fashion. In a rage at what he saw as their arrogant refusal to accept that he was their ruler, he banned Muslim slaughtering and circumcision from his realm for eight years.* Rashid al-Din, the Persian historian, claims that jealous Christian courtiers played a part in poisoning the khan's mind against Muslims. In the end, because Muslim merchants controlled the vital South Seas silver trade, he had to relent.
*Curiously in the decree, Jews are treated as a subset of Muslims.