The Venetian Republic reached its zenith in the dramatic takeover of “a quarter and a half a quarter” of the Byzantine Empire in the Fourth Crusade. It acquired a network of port cities – the Stato da Mar – that enabled its control over trade routes between Europe, Asia, and the Middle East. Called the “hinge” of Europe by one historian, Venice spearheaded an economic leap forward on the continent through a mastery of long-distance navigation. This was Italy’s second great urban age, as cities saw resurgences from the dramatic declines into feudalism in late antiquity. Venice was the prototypical world city of the time, competing with Genoa for control of seaborne trade routes. Indeed, the activities in Italian city-states are critical to the scholarly understanding of the European economic revivals in the ninth and eleventh centuries. The city figures centrally in major works by Janet L. Abu-Lughod, Michael McCormick, Henri Pirenne, and Fernand Braudel for fostering seminal forms of intercity relations at crucial times. Its relations with Constantinople, for example, were of equal importance with those of its Italian neighbors.

Classical Greece was a high period for city networks, with trading centers dotting the map of the Aegean Sea like “frogs around a marsh” in the words of Aristotle. These were strange times, where Spartans annually declared war on their slaves. Where the Athenian reformer Solon banned the export of vital foodstuffs – on penalty of death – while at the same time laying the groundwork for unprecedented political pluralism. Yet we see an uncommon iteration of city networking that was well ahead of its time. Embedded in the lives of these cities was an early echo of the modern. Athens was the alpha city in a polis system of autonomous city-states that, at its height, spanned from Spain to Africa to the Black Sea with a total population of thirty million people. This was an incredible period of seafaring. Language, culture, aesthetics, and revolutionary political ideas flowed in the currents alongside goods and services in an elaborate trading network. Far from localized cultures of self-sufficiency, most Greek cities depended on trade for basics such as foodstuffs, but also for military, intellectual, and cultural production.

Alexander the Great envisioned a city network designed to control “spear won” territory in the wake of his conquests. Alexander imagined a world bridging Greek and Asian cultures – a new era of globalization. He was willing to force whole populations across continents to this end, via city mergers, mass deportations, and resettlements. From its Macedonian foundations, the Hellenistic Age had urban roots. Greek economic influence spanned from Afghanistan to the Atlantic. Trade increased markedly, as did cultural exchange. There was unprecedented hybridization, closely reflected in city building. The urban form dwarfed what existed in the old poleis. Their geopolitical importance increased under territorial empires, the dominant form of statecraft. Cities managed flows of resources. They defended trading routes against nomads, projecting royal military power. Out of Alexander’s splintered empire, his namesake Alexandria was the closest realization of his global vision. There were darker sides to this: Alexandria was part of a system entailing political domination over peripheral zones.

The caliph Al Mansur literally forged the city plan in fire in 762 CE. His Round City was an architectural symbol of order in a vast combustible empire. Ninth-century Baghdad had relations extending from the Atlantic to China, with tranches of coins found as far afield as Scandinavia. The city was by design the heart of a vast city network at a time of pronounced urbanization, an urban golden age by standard reckonings. At the height of Abbasid power its population was an estimated 840,000. It thereby stretched the geographic boundaries of time and space across Eurasia, a Silk Roads terminus in its own right. Baghdad was one of the world’s preeminent “open cities,” incubating trade, knowledge in art, astronomy, mathematics, amidst a myriad of other cross-cultural exchanges. It attracted generations of scientists, philosophers, planners, and literati, especially from Central Asia. Migratory flows included a durable revolving network linking Baghdad to Merv and other key centers of learning and trade along the Silk Roads. Rapidly expanding Islamic civilization had to develop new forms of city building to spread Dar al Islam (the realm of Islam) across vast disparate realms.