The Ferghana also agreed to send two Heavenly horses each year to the Emperor, and lucerne seed was brought back to China providing superior pasture for raising fine horses in China, to provide cavalry which could cope with the Xiongnu who threatened China.
In exchange, the Ferghana pledged to send two majestic horses every year to the ruler, and Chinese traders brought back lucerne seeds, which greatly enhanced the quality of pastures for raising high-quality horses in China, ultimately enabling the country to develop a powerful cavalry force to counter the Xiongnu threat.