toll, or because they were reluctant to shed other Muslims' blood, or perhaps because the Syrians had never pledged allegiance to Ali in the first place, even though similar cases were judged to be apostasy by Abu Bakr. This last argument was also put forward to justify the rebellion in a letter directed at Ali and attributed to Mu'awiya. Elsewhere, Ali is said to have barred his followers from cursing the Syrians, saying that it might jeopardize any remaining hopes for a peaceful resolution. One such report is in connection with Hujr ibn Adi and Amr ibn al-Hamiq, both loyal to Ali. When the caliph learned that they were openly dissociating from and cursing the Syrians, he asked them to describe the evil in their actions instead of vilifying them. After the Battle of Siffin, however, Ali introduced a curse on Mu'awiya in the s of his congregational prayers when the latter declared himself caliph in Syria. A report by al-Tabari indicates that Ali directly negotiated with the Kufan tribal leaders and enlisted in his army some 40,000 (), 17,000 of their sons who had reached the fighting age, and 8,000 clients and slaves. In Basra, however, Ali's governor was only able to recruit some 3200 men. Syria In Syria, Uthman's bloodstained shirt was taken from town to town to incite the people to revenge, though the support for the war was also not unanimous there. Among others, Shurahbil ibn Simt rallied support against Ali across Syria, directly accusing the caliph of killing Uthman in his speeches, according to Ibn Muzahim. To show the success of Mu'awiya's campaign against Ali, Bahramian cites a report by al-Tabari, according to which a Syrian soldier told his Iraqi counterpart that their prayers were invalid because they were led by Ali. Mua'wiya also secured the Byzantine borders by agreeing to a truce at the cost of a "humiliating" tribute to them. He left the protection of his western borders to three local Palestinian commanders, probably because Muhammad ibn Abu Bakr faced internal problems as Ali's new governor in Egypt. Comparisons Siffin is described in Arabic sources as a conflict between the people of Iraq and Syria, in which most tribes were represented on both sides, such as the Banu Kath'am, which was divided to Iraqi and Syrian branches. The number of troops is uncertain. For instance, both armies numbered around 150,000 by one report,