Lecture 39: The Medieval Malthusian Cycle, 500–1350
where powerful small trading states À ourished. Some, such as Venice, were
ruled by merchants.The history of Song China (960–1279) illustrates the transformative power
of these changes. Since it was ¿ rst uni¿ ed in 221 B.C.E., China had been the
very epitome of a traditional Agrarian era tribute-taking empire. Its rulers
controlled huge revenues produced mostly from the land, and like most
Agrarian elites, they despised commerce even though markets were vital to
the Chinese economy.In the 10th century, northern China was conquered by dynasties originating in
Manchuria and Tibet. Suddenly, China was divided into three large warring
states. Con¿ ned to the south, rulers from the Song dynasty faced huge
defensive problems and shrinking revenues, so they had to seek revenues
from new sources, including commerce. In just 200 years, the share of
revenues from foreign trade rose from 2% to 20%. Not surprisingly, the Song
began to back traders and encourage trade.As our model predicts, in such a highly commercialized environment,
innovation accelerated. In a now-classic study, Marc Elvin described the
remarkable acceleration of innovation in this era. There were innovations in
agriculture (including the introduction of new strains of rice from Vietnam,
with active government support), in manufacturing (government factories
produced 32,000 suits of armor each year in the late 11th century), and in
weaponry (this was when gunpowder ¿ rst began to be used in war). Was
China perhaps on the verge of an early industrial revolution? Particularly
striking were advances in naval technology in this period. These would make
possible an astonishing series of state-sponsored voyages to India, Arabia, and
Africa in the early 15th century, under the command of the Muslim admiral
and eunuch Zheng He. In 1279, a Mongol dynasty, the Yuan, reunited China
under a ruler named Kublai Khan, and in 1368 the Yuan were overthrown
by a new Chinese dynasty, the Ming. With fewer rivals and a much larger
tax base, government practice slowly reverted to the anticommercial, tribute-
taking methods of earlier times, and governments stopped backing commerce
and trade. The Ming even tried to ban foreign trade.