• Most significant threat came from Xiongnu nomads
• Along with Qin, attempted to move the Xiongnu with network of northern walls
• Early court attempted to avoid war with Xiongnu by sending lavish gifts
• In treaties with Xiongnu, recognized the nomadic state as equal
• In 145 BCE, a young ambitious emperor, Han Wudi, took the throne
  • He greatly strengthened the army, launched a massive horse-breeding campaign
  • In 134 BCE, he began a series of military campaigns against the Xiongnu
• Relations with Xiongnu had consequences for relations with the outside world
• Chinese identity changed and incorporated many aspects from the Xiongnu nomads