Such perfection endures. For more than two millennia after horse-riding was invented, the warhorse remained the most important military technology bar none. A plentiful supply of horses was critical even in the 19th century, well after firearms had replaced the bows and arrows. Have you ever wondered why Napoleon, who won all of his battles until 1812, lost one battle after another in 1813 and 1814, leading to defeat and abdication? The surprising answer is: horses.