The Manchus were originally Mongol and Tungusic forest tribes from northeast of the Great Wall of China. They hunted, fished, and trapped for a living and traded ginseng and sable furs with Ming garrisons on the Liaotung peninsula. As the more successful tribal chiefs established farms and estates in the frontier zone between themselves and the Wall, an agrarian civilization similar to that of China grew up. By 1644, the time of the Manchu invasion of China, Manchu tribesmen had learned how to mine and smelt iron for tools and weapons. Their tribal organization was highly structured. For some time the Ming garrisons controlled these tribes more or less successfully by playing one against the other and giving various preferments and titles in the Ming army. Dragon robes and dragon silks were very acceptable diplomatic gifts and bribes to the Manchus, as to all their neighbors.