Identification or categorization of migrants and travelers along ethnic and religious lines has been an ongoing concern of modern nation-states. Even the early-modern states were challenged, when individuals left their usual territorial boundaries. In the seventeenth century, a major concern of the Ottoman Empire was efficiently taxing its subjects on move. In this paper I will analyze the mechanisms introduced by the Ottoman state to maintain and recover its locality-based tax revenue in the face of the massive and unceasing movement of its subjects within and even outside the empire. Furthermore, I will argue that the ethnic categorization of the population by the Ottoman state was initiated by the concern for tax collection. The paper will first introduce two different forms of taxation of non-Muslim migrants, namely the perakende (dispersed) poll tax and yava poll tax, which applied to permanent and temporary migrants respectively. Secondly, the perakende maktu’ (dispersed lump-sum) tax will be analyzed as a further stage in the taxation of migrants. Being an individual and non-register-based tax introduced in response to the wave of migration from Anatolia, the lump-sum tax necessitated the state to distinguish the Armenian and most importantly Anatolian-Roman (Karamanli) identities from other ethnic groups affiliated with the Roman-Orthodox Church, such as Albanian, Bulgarian, Laz, Serb, and Rumeli Roman (Greek). While the methods of identification remain unclear, the widespread use of individual tax-receipts for the collection of the lump-sum tax led to the introduction of universal and standardized poll tax receipts, which applied to all non-Muslims, in 1691. Hence, the new tax system also established the first identity paper system in the Ottoman Empire. Notably, these poll tax receipts were used as passports by Austrian authorities in the eighteenth century. Finally, I will argue that the state’s ability to identify individuals with papers eventually facilitated the introduction of the domestic passports. Despite being introduced as a measure exclusively for Greeks in the 1820s, the domestic passports soon turned into universal documents of identification and remained so until 1908.