Improvements in the ability to train horses soon allowed them to be used to pull chariots, possibly as early as 2100 BC, and their greater speed and power made chariots even more efficient. The major limitation of the use of chariots was terrain; while very mobile on flat, hard, open ground, it was very difficult to traverse more difficult terrain, such as rough ground, even sparse trees or bushes, small ravines or streams, or marsh. In such terrain, chariots were less maneuverable than common foot soldiers, and later cavalry.

The chariot