It is hard to exaggerate the influence on Israeli religion, politics and public life of Rabbi Ovadia Yosef, who died Monday at the age of 93. For millions of Israelis – some 800,000 of whom attended his funeral in Jerusalem Monday night – Yosef was the embodiment of religious piety, learning and Sephardi pride.

His religious rulings, famously composed of long compendia of past rabbinic opinions, showcased his vast, encyclopedic knowledge of Jewish law. His was a genius matched by few living Jews.

And he used that genius to correct a historic wrong: the shunting aside of Sephardi Jewish immigrants in the early years of the Jewish state. Born into an Iraqi Jewish family, Yosef took great pains throughout his career to appeal to Sephardic Jewish communities that were starkly different from his, successfully uniting religious Yemenites, Moroccans, Algerians, Egyptians and others both in religious doctrine and, from the 1980s onward, under the banner of the Shas party.

Political founder, ethnic unifier, unparalleled legal genius, religious mentor to a generation of successful Sephardic politicians, Maran — or “master” as his followers called him — was the political and spiritual heart of the Shas movement.

In that sense, his passing marks the fading of an age. No single Israeli was more central to the reclaimed pride of Sephardic Jewry in a state founded by a narrow Ashkenazi elite. And, perhaps, no single Israeli generated more political opposition than the politician-rabbi whose electoral power was founded on ethnic division and resentment.

His passing also marks a political crisis for the movement he founded. Shas’s leadership, both the political and the religious, is divided into two opposing factions: supporters of former party chief MK Eli Yishai and those of the current leader MK Aryeh Deri. The divide is also rabbinic: Yishai supports former chief rabbi Shlomo Amar to replace Yosef as Shas’s spiritual and political supreme leader, whereas Deri seeks an heir either in Yosef’s son, the current Sephardi Chief Rabbi Yitzhak Yosef, or in Rabbi Shalom Cohen, head of the Porat Yosef Yeshiva and a member of Shas’s four-member Council of Torah Sages.

With the old master who kept them united in shared allegiance to him now gone, the party faces the very real danger of splitting along that factional divide.

The two camps – Yishai-Amar and Deri-Yosef – have a history of bad blood between them.

Deri was the political genius behind Shas’s rapid rise to power in the 1980s. He was Israel’s interior minister at the tender age of 29, a role in which he garnered praise from unexpected quarters, including legendary Jerusalem mayor Teddy Kolek, a Labor Party man who nevertheless called Shas’s first interior minister the most effective Israel had ever had.

Deri’s ascent was followed by an abrupt fall when he was convicted of bribery in 2000 and sentenced to three years in prison. He announced his return to politics in mid-2011 and managed to obtain Ovadia Yosef’s blessing to lead Shas once again in October 2012, unceremoniously ousting Yishai as party leader ahead of the January 2013 national elections.

Deri’s return from the political desert was swift and comprehensive. Last year, he worked hard to stymie the efforts of then-chief rabbi Shlomo Amar to be reelected to a second 10-year term. Amar was too closely identified with Yishai, he felt. Deri preferred Ovadia Yosef’s son, Yitzhak, who was eventually elected chief rabbi in July 2013.

Deri’s closest confidante, MK Ariel Atias, was placed third on the party list, ensuring his appointment as Knesset faction chair in charge of the party’s legislative agenda.

It was a rapid takeover, made possible by the all-important support of Rabbi Ovadia Yosef.

Now, all eyes are on Shas’s top leaders to see if the party’s new leadership can survive the old master’s death.

The challenge to Deri’s power could come quickly. Deri is unlikely to be unseated as party chairman by Shas’s Council of Torah Sages so soon after Ovadia Yosef himself approved his appointment. But Yishai, Deri’s political nemesis, may not need to oust him in order to get out from under his yoke.

By law, a group of MKs can split from their current party and still receive public campaign financing if they take with them at least one-third of the MKs of the party they are leaving. Eli Yishai enjoys the support of several Shas MKs, including Avraham Michaeli and Yaakov Margi. MKs David Azulai and Meshulam Nahari are thought to be wavering between the camps. The loyalty of several others is either unknown or in flux. In fact, of eleven Shas MKs in the current Knesset, Deri can count with absolute surety only on himself and Atias. And since Yishai, bristling under the thumb of his hated adversary, only needs three additional MKs to establish his own financially viable party overnight, the temptation to walk away from Shas may be hard to resist.

Hundreds of thousands of Israelis lost a spiritual guide on Monday. The party he founded lost something more. The party’s very raison d’etre was in its service to Maran. Shas’s leaders will now find themselves faced with two uneasy choices: to unite in fashioning a post-Ovadia party out of the political shell he left behind, or to splinter away into more comfortable fragments destined for political oblivion.