After the fall of the Han dynasty, China was reunified by the Sui dynasty in 589 CE. This began the period of the Sui, Tang, and Song dynasties, which was characterized by political stability, economic growth, and cultural/intellectual achievements. Key developments included the spread of Buddhism, population growth, improved agriculture, expansion of trade via the Silk Road and Indian Ocean, technological innovations in clockwork, gunpowder, paper, and printing, and the growth of cities and a market economy. However, Confucian social structures around scholars, officials, and patriarchy persisted throughout this period.