Inequality began a long time ago, opines Slate's Mary Mycio, when "the association between horses and wealth was forged millennia ago."

[...] the first people known to celebrate hierarchies of power, whose inequalities of wealth were integral to their society and culture -- the people you could call the first 1 percent -- were the first people to ride horses.

Horse domestication occurred before written history and left few clear archaeological remains. Based on Sumerian seals with the earliest known depictions of people on horseback, riding has traditionally been dated to the Bronze Age, around 2000 B.C., in Mesopotamia.

But new evidence is pushing the origins of horse domestication deeper into the past and farther to the north, on the steppes between Kazakhstan and Ukraine, where wild horses were plentiful after the end of the last Ice Age. Excavations in Botai, Kazakhstan, during the 1990s unearthed an amazing 300,000 horse bones (and a few dogs). The researchers also found horse-fat residue on pottery. They concluded that the Botai people were sedentary pastoralists, much like modern-day ranchers, who lived in permanent settlements and herded horses for mares' milk as early as 3500 B.C. People were riding the animals, too: The researchers found horse teeth that had been ground down by bits, the bars placed in horses' mouths that make it possible to control them while on horseback.