referred to the Ghadir Khumm after his ascension to the caliphate in 656. Mavani similarly cites some Sunni and Shia reports, including the proceedings of the electoral council in 644 when Ali refused to be bound by the precedence of the first two caliphs. Another report by al-Tabari indicates that Ali again publicly excluded the practices of Abu Bakr and Umar from the Sunna (of Muhammad) when his supporters pledged their allegiance to him in Kufa. Madelung holds that Ali's views about succession mostly match the Shia beliefs today, and Lalani and Daftary have similar opinions, whereas Veccia Vaglieri considers the Shia beliefs fabricated because Ali "showed no inclination to legitimism." In contrast, Madelung and others detail the opposition of Ali to the appointment of Abu Bakr at the Saqifa. Yet Madelung also highlights some Sunni hadiths in which Ali reportedly praised Abu Bakr and Umar, while some others note the Sunni tendency to minimize and neutralize the conflicts among companions after Muhammad, particularly about the Saqifa affair. In and some other early Shia sources, Ali contrasts the corruption of the third caliph, Uthman, with the political leadership of Abu Bakr and Umar, even though he rejects their religious legitimacy. A related example is the account of the negotiations before the Battle of Siffin (657) by Ibn Muzahim (), which quotes Ali as saying that Abu Bakr and Umar had governed justly, even though they had assumed the caliphate wrongfully. Mavani and Maria M. Dakake suggest that Ali viewed the succession of Abu Bakr as a digression which turned into a full-blown deviation with the rebellion of Mu'awiya during his own caliphate. This is also the Shia view, as represented by the Shia jurist Ruhollah Khomeini (). Tribal politics Banu Aws A question can be raised as to what enabled a handful of the Muhajirun to force their will upon the Ansar at the Saqifa. Ibn Ishaq and Caetani attribute this to an earlier collusion between the Muhajirun and the Banu Aws, the rival tribe of the Banu Khazraj among the Ansar. Madelung rejects this as unlikely but suggests that Usaid ibn Hudair, a chief of the Banu Aws, must have backed Abu Bakr at the Saqifa and carried with him the majority of the Aws, as also apparent from a related report by al-Tabari. Jafri likewise suggests that the deep-rooted enmity between the minority Banu Aws and the majority