After Spain's rule in the New World ended in 1821, Mexico began distributing mission lands, and this area became part of the Mexican land grant Arroyo de las Nueces y Bolbones, a rancho of nearly two square leagues, or roughly 17,000 acres. Mount Diablo's open range provided rich grazing for cattle, and during drought or when herds grew too large, older animals were slaughtered so their fat could be boiled into tallow for soap and candles while their hides were cured and traded to English, Russian, and American merchants along the coast of Alta California. Demand from the eastern United States made cowhides, commonly called California Banknotes, the primary source of wealth in early California and a barter good for products shipped around South America into California harbors. After the discovery of gold in 1849, population rose from 20,000 to nearly 250,000, beef prices climbed to nearly $500 per head, Spanish cattle stocks were depleted, and Texas long-horn and then American cattle were imported. As failed prospectors became farmers and cowboys, often learning from local vaqueros, large Mexican-era ranchos gave way to smaller farms and ranches marked by windmills and barbwire fences. The Pacheco family grazed cattle on this land, sold nearly half of their original rancho to James Walker, who operated a cattle ranch here until the 1880s, and Frank Macedo later purchased 825 acres in 1920 and raised cattle here until 1959; about one quarter of the original rancho is now Mount Diablo State Park. Native Americans had lived on and near Mount Diablo for thousands of years and regarded it as sacred, relying on it for game, seeds, plants, and nuts, but Spanish missionaries founded Mission of San Jose in 1797, converted local Indians to Catholicism, and put many neophytes to work farming and tending cattle. Andalusian cattle introduced in the early 1790s multiplied so greatly on Mount Diablo's slopes that the neophytes were trained to herd on horseback despite Spanish law, and as vaqueros they became the first cowboys.