Negotiated in secrecy between Britain and France in 1916, the Sykes–Picot Agreement constituted a pivotal episode of territorial engineering that reconfigured the Middle East during and after World War I. Designed to partition the Ottoman Arab provinces into imperial spheres of influence, it overlaid schematic straight-line borders upon landscapes shaped by intricate cultural, tribal, and religious networks. By excluding local agency, the agreement inscribed the strategic priorities of the imperial powers into spatial arrangements that were subsequently institutionalized through the League of Nations mandate system. This process produced a state system in which borders preceded national identities, constraining nomadic mobility, fragmenting communal ecologies, and entrenching structural tensions. Artificial frontiers reconfigured plural societies such as Lebanon and Syria, where sectarian divisions were mobilized into mandate-era governance, laying the groundwork for recurrent instability. A century later, the Sykes–Picot Line endures—both materially and symbolically—as a paradigmatic instance of imperial imposition, repeatedly invoked to account for the volatility of the modern Middle East.