Proto-Hittite bronze oxen and wagon
The following essay is from the 1996 publication Gods, Men, and Heroes: Ancient Art at the Dallas Museum of Art.
Other examples of these four-wheeled bronze wagons from Mesopotamia, Syria, and Anatolia are generally attributed to the late third and early second millennia B.C.E. Although very few works come from controlled excavations, the large number of examples, as well as representations of wheeled vehicles in other media, like the famous Standard of Ur in the British Museum, tell us a great deal about the critical early stages of the development of wheeled transport. The Mesopotamian and Syrian examples are commonly horse-drawn and may be war chariots or royal vehicles. The Anatolian carts are generally drawn by oxen or bulls and may be farm carts used for transporting foodstuffs. The openwork structure of the Anatolian carst, as opposed to the high frontal build of the Syrian examples, also suggests a farm cart. In either case, these four-wheeled wagons were developed from sledges and two-wheeled carts. The idea of wheeled vehicles is as critical an invention for human civilization as the development of farming and pastoralism at the beginning of the Neolithic period. It made possible more far-ranging and much faster travel, transportation, trade, warfare, and farming activities. The wheel was introduced into Egypt from the Near East only after the great age of pyramid building. In the Americas, where the wheel was never used for transport in ancient times, probably because the New World lacked suitable draft animals, peoples' movements were limited to foot and llama travel.
It is difficult to overestimate the importance of this development in Eurasia. While the horse may have first been domesticated north of the Black Sea, and the largest number of representations of wheeled vehicles appeared in Eurasia, it still seems likely that the key idea of drawing four-wheeled wagons with draft animals occurred in the Near East sometime in the third millennium B.C.E.
The DMA oxen and wagon is an especially fine work of art. Few other examples of this type have so clean and graceful an outline. The oxen, particularly, are as handsome in their way as the Amlash ram rhyton. The ox figures were cast by the lost-wax method in bronze with a strong copper component. The animals' tails were cold-worked and mechanically attached to the bodies. Both the yoke and the cart were cold hammered. The cart has a flat floor and movable openwork sides, back, and front. The front of the cart frame has a double-curved top. The wheels are solid disks.
Anne R. Bromberg and Karl Kilinski II, Gods, Men, and Heroes: Ancient Art at the Dallas Museum of Art. Seattle: University of Washington Press, 1996. 32.