The Bene Israel claim that they are members of "lost" tribes that reached India as long ago as 175 B . C . According to their tradition, their ancestors were shipwrecked off the Konkan Coast and lost all their holy books; they only remembered the Shema, the Jewish prayer expressing faith in God. They lived among the Hindus and adopted several of their customs. When discovered by a Jewish outsider, David Rahabi, possibly in the eighteenth century, they observed the Sabbath, dietary laws, circumcision, and many of the Jewish festivals, but they had no synagogue. Navyacha San, the New Year, was only celebrated for one day; the rationale for several Jewish fast days appeared to have been forgotten; and Hannukah (the Feast of Lights) was unknown, since it had developed after the Bene Israel departure from the land of Israel.
From 1750 onward, the Bene Israel embarked upon a process of adjusting to mainstream Judaism. They gradually moved from the Konkan villages to Bombay and other cities as their involvement with the British Raj increased. Their first synagogue, named "Gate of Mercy," was established in Bombay in 1796. The Bene Israel were also assisted in their religious life by Cochin Jews from the Malabar Coast, who acted as cantors, ritual slaughterers, and teachers. In the Second half of the nineteenth century, the Bene Israel of Bombay were joined by some Jews from Baghdad (including the Sassoon family), who served as a reference model of normative Judaism. Paradoxically, the arrival of Christian missionaries in the Konkan from 1810 promoted the Bene Israel rapprochement with world Jewry by introducing them to the Hebrew Bible and other religious texts in Marathi translation.
After the British withdrew from India in 1947 and the State of Israel's establishment in 1948, Bene Israel began emigrating to Israel. By 1960, it became clear that certain rabbis in Israel would not marry Bene Israel to other Israelis on Jewish legal ( halakhic ) grounds, alleging that there were doubts concerning their Jewishness. Between 1962 and 1964, the Bene Israel organized a series of strikes and demonstrations in Israel involving the whole community to demand status as "full Jews." In 1964, the Chief Rabbinate withdrew its halakhic objections and declared the Bene Israel "full Jews in every respect."