According to the legend, in 1887 four brothers in Dryden, Texas—Frank, Jim, John, and Lee Reagan—hired an illiterate Seminole named William Kelly to help with work on their ranch.
Stories then conflict: One account states that he returned to Dryden, where the Reagans received a letter addressed to him that confirmed the gold was immensely valuable, and then killed him and dumped his body in the Rio Grande.
[5] As well as the Reagans, many other expeditions set out in search of the mine; the legend has it that, while some explorers did discover it, they always died before they could make a profit or pass on the information.
[5] One of the more serious searches was instigated by William Broderick Cloete, a British mine owner who believed in the story so completely that he offered Lock Campbell, a Texan man, expenses of $10,000 if he would undertake an expedition to find it.
In 1909, an Oklahoman named Wattenberg traveled to Alpine, Texas, with a map that he claimed showed the mine to be in Mexico; a pioneer named John Young went so far as to enter into partnership with Wattenberg and secure a mining permit from Porfirio Díaz, only to spend years fruitlessly trying to find it.