William Muir,
The Caliphate: Its Rise, Decline and Fall…
“ The Al-Kufa ranks were urged on by the regicides, who felt that unless 'Ali conquered, they were all doomed men. The fierceness and obstinacy of the battle can be only thus accounted for. One of the combatants tells us that "when the opposing sides came together breast to breast, with a furious shock, the noise was like that of washermen at the riverside."1 The attitude of the leaders was in marked contrast with the bitter struggle of the ranks. Az-Zubeir, half-hearted since his interview with 'Ali, left the battlefield according to his promise, and was killed in an adjoining valley. ”
