 Complete the following phrase:  In 209 BC, three years before the founding of Han China, the Xiongnu were brought together in a powerful confederation under a new chanyu, Modu Chanyu. This new political unity transformed them into a more formidable state by enabling the formation of larger armies and the ability to exercise better strategic coordination. The Xiongnu adopted many of the Chinese agriculture techniques such as slaves for heavy labor and lived in Chinese-style homes. The reason for creating the confederation remains unclear. Suggestions include the need for a stronger state to deal with the 