Thanks to the peculiarities of Arabic grammar, the vast majority of Abbasid caliphs in the 9th-13th centuries had three-, four- or five-syllable names beginning "al-Mu..." During the 865 civil war in Baghdad between two cousins for control of the caliphate, one of the defenders mistakenly cried out the name of the usurper, al-Mu'tazz, instead of the incumbent, al-Musta'in. He was promptly put to death, or so the chroniclers tell us. One wonders if he was coached by the attackers, a kind of "Rabbit season!" "Duck season!" strategy.