In 1540–1541, who was the first European explorer to explore the area that would become Oklahoma?

The first European explorers to visit the territory of future Oklahoma in 1541 were thirty-six soldiers under the command of Francisco Vasquez de Coronado, the Spanish governor of the New Galicia province of the Spanish colony New Spain (now Mexico). The Coronado expedition was looking for the so-called Seven Cities of Cibola and their fabled wealth. Finding no gold or silver, the expedition was quite disappointed. Its Native American guide, whom the Spanish called El Turco, told them of the wealthy civilization of Quivira in what is now Kansas. Spanish soldiers crossed the future Oklahoma on their way from Texas to Quivira. Quivira was very populous, but it also lacked gold and silver. Coronado ordered the execution of their Native American guide as he believed that El Turco had deliberately deceived them. In 1542, the Spaniards returned to Mexico after failing to discover riches, but they had explored and mapped a substantial region of the future US, including parts of Texas, Kansas, New Mexico, and Oklahoma.