Abu Bakr was near-universally accepted as head of the Muslim community (under the title of Caliph) as a result of Saqifah, though he did face contention because of the rushed nature of the event. Several companions, most prominent among them being Ali ibn Abi Talib, initially refused to acknowledge his authority. Among Shi'ites, it is also argued that Ali had previously been appointed as Muhammad's heir, with the election being seen as in contravention to the latter's wishes. Abu Bakr later sent Umar to confront Ali, resulting in an altercation which may have involved violence. However, after six months the group made peace with Abu Bakr and Ali offered him his allegiance.
