FEZ — The sight of 72,000 people rushing into the Spanish enclave of Ceuta from neighboring Morocco was a blunt reminder that one of the European Union’s most sensitive land borders is in North Africa. The status of Ceuta and Melilla, another Spanish enclave within Morocco, has been a simmering political dispute between the Moroccan and Spanish governments for many decades. Morocco claims sovereignty over these cities, whereas Spain maintains that they are as much a part of its national territory as Madrid. For centuries, the Muslim dynasties that ruled the western Maghreb and al-Andalus controlled Ceuta, until King John I of Portugal captured it in 1415—a precursor to European expansion overseas. When the Portuguese monarchy came under the control of the Spanish Habsburgs in 1580, so, too, did Ceuta. Following the restoration of Portuguese independence in 1640, the city remained loyal to the Spanish monarchy. As the great French historian Fernand Braudel observed, the Mediterranean should be understood as a historically interconnected theater, shaped by migratory, commercial, cu