This paper investigates the relationship between identities and political allegiances on premodern frontiers. The first half of the paper is a case study of interactions between Turks and Chinese elites and commoners during the Sui-Tang dynastic transition. The second half compares Roman, mid-imperial Chinese, and early Islamic frontiers. The paper concludes that people in frontier zones tended to forge political ties based on self-interest and personal connections. Solidarities based on ethnic or religious allegiance were rare because premodern state power, transportation, and communications could not spread these ideals effectively.One example is the Iberian frontier (al-Andalus) during the middle ages.
The Iberian frontier zone from the eighth to eleventh centuries presents a familiar picture of mixed ethnicities, identities, and political affiliations. Although the Islamic sources paint an image of a clear division between Muslim holy warriors and "infidel" Christian kingdoms, the reality was far different. The Iberian Umayyad dynasty (756-1031), which ruled the southern half of the peninsula, had only a loose reign over the Arab, Berber, and indigenous convert aristocratic families who controlled the borderlands. The loyalties of the frontier aristocrats were constantly shifting as they engaged in relations with the Umayyads, Christian kingdoms, and each other. Sharing only an aversion to central control, self-interest was more important than ethnic or religious affiliation in determining political alliances .... The situation on this frontier should give pause to those who assume that an ideology of jihad, in its guise as holy war, has always been an essential part of Muslim political life. Clearly, the limited power of the Iberian Umayyad state played a role in its inability to regulate the frontier and enforce political loyalties more effectively.