182 cities: Africa Portuguese caravels began sailing down the West African coast, disrupting trading ports and carrying out a murderous trade in slaves and gold As Europeans established depots and trading stations in West and East Africa, Christian missionaries followed them The effort to settle and exploit Africa’s human and natural resources brought about new concepts of city design and function in sub-Saharan Africa Fall of Rome and Alexandria The city of Alexandria, founded by the Macedonian general Alexander the Great in the fourth century b.c.e., remained the busiest port in the Mediterranean for several centuries A vital link in the importation of grain from the Nile River valley to Rome, Alexandria was a major harbor and a city of fine palaces, mansions, and public buildings laid out on a regular grid of streets divided into four major quarters As a cultural center Alexandria was unsurpassed in the Mediterranean world; it was home to respected philosophers and astronomers, and its library and academies were renowned throughout the empire The decline of the Western Roman Empire in the fifth century wrought a transformation in the city As its harbor declined in importance, Alexandria lost population and grew isolated from the Nile Valley as well as the new center of imperial authority, the eastern capital of Constantinople (modern-day Istanbul), far to the north on the bridge between Asia Minor and Europe Pagan temples and monuments in Alexandria were thrown down by the dominant Christians, and the city’s libraries and academies were largely abandoned In 616 Alexandria was overrun by a Persian army under King Khosrau II An Arab army arrived to lay siege in 641; the citizens endured 14 months of assaults before the city finally surrendered in 642, having lost its renowned library and the thousands of manuscripts contained within it The Arab conquest of Egypt and North Africa that soon followed destroyed the last remnants of Roman culture on the continent and began an era of Islamic domination of North African cities, trade, religion, and culture that has lasted to the present Axum In the early Middle Ages, while Alexandria declined into a small and isolated coastal settlement, the Axum Empire of northern Ethiopia was prospering The abundant rainfall in the region allowed its farmers to produce two harvests every year Terracing of the mountainsides increased the area under cultivation The bumper crops and the wealth that flowed along trading routes between mountainous Ethiopia and the Red Sea created a prosperous merchant class whose members spent their disposable income on luxury items created by artisans in wood, stone, gold, and gems By the fifth century c.e the capital of Axum was one of the wealthiest cities in Africa Axum drew a large population of migrants and foreigners while extending its power to far-flung valleys and towns in the Ethiopian highlands Trade through the Red Sea port of Adulis linked the city to India, Persia, and the Mediterranean ports of the Byzantine (Eastern Roman) Empire The city imported cattle, iron, and salt while exporting luxury goods from the interior of Africa, including ivory, rhinoceros horn, gold, spices, frankincense, and war elephants Metalworking technology arrived from the Middle East via the Nile Valley, giving rise to a busy iron industry; Axum was one of the first realms in sub-Saharan Africa to mint its own coins Beginning in the fourth century the Axumites adopted Christianity through links to the eastern Mediterranean (Christianity remains an important faith in modern Ethiopia.) The Axumite nobles built impressive mansions in the city and provided a market for expensive cloth, wine, glass, and spices from Arabia and the Levant The Axumite kings celebrated their lives and their reigns by raising tall obelisks, more than 100 of which eventually fell and now litter the streets and parks of the modern town of Axum The tallest of these monuments was 108 feet high The most elaborate obelisks had detailed bas-reliefs carved into their surfaces Axum began a slow decline soon after the fall of the Roman Empire, which had traded with Axum via Egypt and the lower Nile Valley Axum’s foreign markets either vanished or were besieged and conquered by Islamic armies sweeping across the eastern Mediterranean and down the coast of the Red Sea The city’s farming hinterland also suffered environmental damage As trees were cut down to provide wood for the furnaces of metal foundries and for the manufacturing of brick and glass, the soil began to erode, and crop yields suffered The situation worsened as rainfall began to decline in the eighth century; the port of Adulis was conquered by the Arabs in the same period, and Axum’s main link to the outside world, and its main source of revenue, disappeared Urban society grew tumultuous, with violent revolts brewing in the streets and hunger rampant The city’s nobility took refuge in isolated hilltop fortifications and then moved to central Ethiopia, leaving Axum a poor and sparsely inhabited ghost town The Axum Dynasty was finally toppled and Aksum itself destroyed in the 10th century, after an assault by Queen Guldit, a determined opponent of Christianity In 1137 the Zagwe rulers ascended to power from their capital at Roha in the Lasta Mountains In this northern town (modern-day Lalibela), a series of 12 rock-cut churches were constructed during the reign of King Gebre Mesqel Lalibela, which ended in the early 13th century This Christian king envisioned Roha