ALARCON, Hernando d' (ah-lar-kon'), Spanish navigator, born early in the 16th century. He sailed from New Spain in May 1540 with two ships and a tender along the western coast of America, under instructions from Mendoza, the viceroy, to aid the land expedition of Coronado, which set out at the same time, in search of the seven cities of Cibola. He made a careful survey of the shoreline of the Californian peninsula, previously supposed to be an island, and returned to New Spain in 1541, having failed to meet the land expedition according to the plan. He also discovered the Colorado River, ascended that difficult stream for 100 miles, and took possession of the country in the name of Charles distributing crosses among the natives as a missionary of the Church, telling them that he was the "messenger of the sun." His charts and observations, supplementing those of Ulloa, accurately represented the configuration of California.