This paper investigates Ibadi accounts of the debate (munazara) with the khawarij at Harura` that are preserved in al-Qalhati’s al-Kashf wa al-Bayan, al-Izkawi’s Kashf al-Ghumma, al-Barradi's Kitab al-Jawahir and al-Shammakhi's Kitab al-Siyar (among other places). Although these versions share many core similarities with non-Ibadi munazara accounts, they provide a counter-perspective to those that can be found in the standard Sunn? histories. In them, 'Ali and/or ‘Ali b. Abi Talib’s representative, ‘Abdullah b. al-‘Abbas, leave the debate convinced by the soundness of the Kharijites’ arguments. The Ibadi versions of the munazara thus provide a rationale for accepting Ibn al-‘Abbas as an intellectual founding figure of the Kharijite- Ibadi school of thought. Indeed, Ibn al-‘Abbas is known among the Ibadiyya as bahr al-‘ilm (“the sea of knowledge”). By appropriating Ibn al-‘Abbas’ reputation for piety and learning – a reputation that existed within Sunni circles as well – the Ibadiyya bolstered their own claims to exclusive Islamic validity. This paper will compare Ibadi versions of the munazara with those found in al-Tabari and al-Baladhuri, as well as with the fragmentary reports in Sunni heresiographical texts. It will highlight the use of history as the creation and maintenance of legitimating narratives that defend doctrinal positions and authenticate connections to an Islamic past by exploring the genre of munazara as the mechanism by which sect-specific versions of the story were created.