Since their inception Arabic and Persian historiographies have produced a relatively coherent set of information about the Kurds. Historians can read in these texts elements that defined the boundaries of Kurdish medieval identity. Although the latter was constantly constructed and reconstructed, this potentially infinite process was technically limited by a series of factors. Boris James will focus on two historical situations each one highlighting one factor that contributed to the shaping of Kurdish medieval identity. The first lies at the beginning of Arabic historiography (10th - 11th centuries) when Kurdishness was an implicit category defined in opposition or association with ‘arab or ‘ajam categories in the context of the domination of an Arab caliphate. Arab authors first tried to understand ethnic differentiation based on familiar tools existing in Bedouin societies; primarily the fragmentation into tribes and clans and membership of a lineage dating back to an eponymous ancestor. This limited range of analytical tools also possessed a political and ideological aspect – namely the need to maintain the cohesion of the early caliphate and its army. The second period starts with the collapse of the Ayyubid dynasty and the beginning of the Mamluk regime (second half of the 13th century). Kurdish identity underwent then a specific reproduction due to the shift of its political and military role in the context of marginalization in Syria and Egypt and war between the Mongols and Mamluks. Mamluk policies were somewhat paradoxical, promoting both integration and differentiation. These policies reflected their desire to create a powerful coalition against the Mongols through reinforcing the notion of the Kurds as a distinct category, while at the same time territorializing it.