With the establishment of the State of Israel in 1948, and the riots and persecutions that resulted against the Jews of Arab countries, massive numbers of Middle-Eastern Jews were brought to Israel. The Israeli leadership, consisting largely of secular Ashkenazic Jews, often viewed the religious lifestyles of their "oriental" cousins as another manifestation of the cultural primitiveness that would have to be shed as part of their integration into a modern Western society. Many of the immigrants were persuaded to abandon the religious traditions of their former homelands.
During the first decades of Israeli statehood, North African Jews did not establish their own political or religious movements or institutions, and most were absorbed into the established Ashkenazic bodies. They were usually educated in the State Religious School System (even when religious Ashkenazim were sending their children to private religious schools and yeshivahs). The main religious political movements, the Aguddat Israel and the Mizrachi (which evolved into the National Religious Party), had few Sepharadim among their leadership.
By the mid-1970's the ethnic divisions between Ashkenazic and Sepharadic Israelis became a major social issue.
In the religious sphere this involved the creation of Sepharadic parallels to the mainstream religious parties
The upshot of this was the creation of a Sepharadic equivalent to Aguddat Israel, named "Shas," with its own Council of Torah Sages.
The principal spiritual leader of the party is the renowned halakhic authority Rabbi Ovadiah Yosef. The Israeli government's refusal to extend Rabbi Yosef's term as Sepharadic Chief Rabbi (Rishon Letzion) had been one of the main reasons for the Shas party's establishment.