Guillermo Castro was the son of Carlos Castro of Rancho San Francisco de las Llagas

Rancho San Francisco de las Llagas

Rancho San Francisco de las Llagas was a Mexican land grant in present day Santa Clara County, California given in 1834 by Governor José Figueroa to Carlos Antonio Castro...

, near Coyote

Coyote Valley

Coyote Valley is a large expanse of farmland, orchards and homes, approximately in size, located in a narrowing of the Santa Clara Valley, in the southernmost part of San Jose, California...

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 in Santa Clara County

Santa Clara County, California

Santa Clara County is a county located at the southern end of the San Francisco Bay Area in the U.S. state of California. As of 2010 it had a population of 1,781,642. The county seat is San Jose. The highly urbanized Santa Clara Valley within Santa Clara County is also known as Silicon Valley...

. He was a soldier, rancher, surveyor, and magistrate in his lifetime.

Biography

Castro was a career solidier and lieutenant of the militia in the Mexican

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 army, posted to the Pueblo of San José. He also worked as a surveyor for the government (listed as such in 1838). Three years later, in 1841, Governor Juan Alvarado granted Castro 26722 acres (108 km²) as a reward for service. The grant, called Rancho San Lorenzo, included much of what is today Castro Valley

Castro Valley, California

Castro Valley is a census-designated place in Alameda County, California, United States. As of the 2000 census, it is the fifth most populous unincorporated area in California, and the twenty-third in the United States...

, Hayward

Hayward, California

Hayward is a city located in the East Bay in Alameda County, California. With a population of 144,186, Hayward is the sixth largest city in the San Francisco Bay Area and the third largest in Alameda County. Hayward was ranked as the 37th most populous municipality in California. It is included in...

, and San Lorenzo

San Lorenzo, California

San Lorenzo , also known as San Lorenzo Village is a census-designated place in Alameda County, California, United States. The population was 23,452 at the 2010 census.-Geography:...

.

Soon after receiving his land grant, Castro married Luisa Peralta of the Rancho San Antonio (owned by Luís María Peralta

Luís María Peralta

Luis María Peralta was a soldier in the Spanish Army, who received one of the largest of the Spanish land grants, Rancho San Antonio, a plot that encompassed most of the East Bay region of California.-Biography:...

, possibly Luisa's father). The young couple received 300 cattle as a wedding gift. As a rancher, Castro added 4000 sheep and 500 horses, and in the next 7 years, 7 children. The adobe

Adobe

Adobe is a natural building material made from sand, clay, water, and some kind of fibrous or organic material , which the builders shape into bricks using frames and dry in the sun. Adobe buildings are similar to cob and mudbrick buildings. Adobe structures are extremely durable, and account for...

 home of the couple was discovered years later beneath the foundation of the old Hayward city hall.

Over the next 26 years, Castro set himself on the path to self-destruction, due to his compulsive gambling. He began selling off portions of his rancho to cover his gambling debts, finally mortgaging his property. To add to his financial problems he had to pay for lawsuits to force squatters off his land, brought by the influx of settlers from the California Gold Rush

California Gold Rush

The California Gold Rush began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The first to hear confirmed information of the gold rush were the people in Oregon, the Sandwich Islands , and Latin America, who were the first to start flocking to...

. One squatter he tried to evict, and later hired, was William Dutton Hayward for whom the city of Hayward was later named. In 1864, sheriff I. A. Mayhew presided over the sale of the last of the rancho for 400,000 dollars to Faxon Atherton

Faxon Atherton

Faxon Dean Atherton was an American businessman and landowner, and was a prominent citizen of San Mateo County, California. He is the namesake of Atherton, California.-Early life:...

. Destitute, Castro left California for Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

 with his wife and younger children.

A contemporary, Jacob Harlan said of Castro, "Of the Spanish Californians that I have known, Guillermo Castro was the best. He was a sparse, wiry man with brown eyes and hair and was physically active and tough. He was a splendid horseman and he was very extravagant and spent his money freely."