The Beta Israel, though somewhat disputed as the descendants of the ancient Israelites, are widely recognized in Israel as Ethiopian Jews. The ancestry of most American Jews goes back to Ashkenazi Jewish communities that immigrated to the US in the course of the 19th and 20th centuries, as well as more recent influxes of Persian and other Mizrahi Jewish immigrants. The American Jewish community is considered to contain the highest percentage of mixed marriages between Jews and non-Jews, resulting in both increased assimilation and a significant influx of non-Jews becoming identified as Jews. The most widespread practice in the U.S is Reform Judaism, which doesn't require or see the Jews as direct descendants of the ethnic Jews or Biblical Israelites, but rather adherents of the Jewish faith in its Reformist version, in contrast to Orthodox Judaism, the mainstream practice in Israel, which considers the Jews as a closed ethnoreligious community with very strict procedures for conversion. The Jews of modern France number around 400,000 persons, largely descendants of North African communities, some of which were Sephardic communities that had come from Spain and Portugal—others were Arab and Berber Jews from Algeria, Morocco and Tunisia, who were already living in North Africa before the Jewish exodus from the Iberian Peninsula—and to a smaller degree members of the Ashkenazi Jewish communities, who survived WWII and the Holocaust. Mountain Jews are Jews from the eastern and northern slopes of the Caucasus, mainly Azerbaijan, Chechnya and Dagestan. They are the descendants of Persian Jews from Iran. Bukharan Jews are an ethnic group from Central Asia who historically practised Judaism and spoke Bukhori, a dialect of the Tajik-Persian language. The Kaifeng Jews are members of a small Jewish community in Kaifeng, in the Henan province of China who have assimilated into Chinese society while preserving some Jewish traditions and customs. Cochin Jews also called Malabar Jews, are the oldest group of Jews in India, with possible roots that are claimed to date back to the time of King Solomon. The Cochin Jews settled in the Kingdom of Cochin in South India, now part of the state of Kerala. As early as the 12th century, mention is made of the Black Jews in southern India. The Jewish traveler, Benjamin of Tudela, speaking of Kollam (Quilon) on the Malabar Coast, writes in his "Itinerary": "...throughout the island, including all the towns thereof, live several thousand Israelites.