Recent scholarship on Ottoman history has stressed the beginning of the 16th-century as an era in which confessional identities strongly crystallized. It has been argued that the Empire’s Sunni identity developed as a strong force against the emergence of a Shiite Safavid Empire. Recent Ottomanist scholarship has viewed the 15th-century as an era of “confessional ambiguity” or “metadoxy”, whereby no clear distinction existed between orthodox and heterodox versions of Islam in the Ottoman polity. In this paper, I will be focusing on a major representative of 15th-century Ottoman Sufism, Eşrefoğlu Rumi (d. 1469) and his work Tarikatname (Book of the Sufi Path). Written as a manual for Sufi initiates to choose the ideal path and Sufi guide, this work opens a window into the ideals of 15th-century Ottoman Sufi piety. While Eşrefoğlu Rumi favors a Sunni Sufi path, he attributes a special position to Ali b. Abi Talib. Considering Eşrefoğlu Rumi’s position, I would argue that, at least in the eyes of pious individuals like himself, there was a distinction between “the right path” of Islam and what these pious individuals regarded as more “heretical” ways that they condemned. Later conceptualizations of Ottoman “orthodox” Sunni Islam tended to emphasize a clash between the “orthodox” and Sufi versions of Islam. However, Eşrefoğlu Rumi’s work demonstrates otherwise. Sufism and his 15th-century pious “orthodox” understanding of Islam were not mutually exclusive within the evolving Ottoman religion-political milieu. Similarly, the fact that Ali held a special place in Eşrefoğlu Rumi’s Sufi ideals does not indicate that he strayed from his Sunni position. On the contrary, the special place attributed to Ali originates from the latter’s established image as the ideal “friend of God”. This paper will demonstrate Eşrefoğlu Rumi’s attempts to articulate his version of “orthodoxy” in the context of an evolving Ottoman imperial vision under Mehmed II (d.1481). In addition, it will analyze his Sufi ideals within the paradigm of the vernacularization of Islamic culture and piety in Ottoman Anatolia. Tarikatname thus provides the modern historian with a framework to discuss and reconsider the definitions of confession and orthodoxy, and illuminate Sufi piety and mentalities of the 15th-century.