Founded in 960 by the general Zhao Kuangyin, the Song dynasty reunified a fragmented China and presided over three centuries of explosive innovation. Song China reached a degree of urbanisation and population density no contemporary civilisation matched; the capital Kaifeng, with close to a million inhabitants, may have been the largest city in the world.

Three of China's 'four great inventions' matured in this period. Around 1040 Bi Sheng developed movable type from fired clay — four centuries before Gutenberg. The magnetic needle was used for the first time to navigate at sea. Gunpowder moved from fireworks to firearms — fire arrows, bombs and primitive cannon. To this was added the first widespread state use of paper money.

The economy was transformed too: steel production, coal mining, water-powered machinery and a vast network of internal trade created a surge that some historians call a 'medieval economic revolution.' An examination-based bureaucracy and Neo-Confucian thought formed the backbone of state and culture.

The Song, under nomadic pressure from the north, first withdrew to the south and were then destroyed by the Mongols in 1279. But their inventions spread westward through the Islamic world and along the Silk Road; printing, the compass and gunpowder would, centuries later, become era-changing tools in Europe.