For what did Captain Robert Gray first achieve fame?

Robert Gray was born in Tiverton, Rhode Island on May 10, 1755. In 1787 Captain Gray and Captain John Kendrick were sent out by their backers from Boston with a cargo of buttons, beads, blue cloth, and other items to bargain with the Oregon coastal native tribes for the pelts of sea otters. Kendrick stayed to continue trading while Gray sailed on to the Orient in the full rigged ship, the ‘Columbia Rediviva’ (usually called the ‘Columbia’), to sell the pelts and to buy tea and possibly silk and spices. To complete the voyage, Gray sailed west to Boston, becoming the first American to circumnavigate the globe.

Gray's other notable achievement came on his second voyage to the Oregon coast in 1792. He pursued his belief that there was a "Great River of the West" to discover. On May 11, 1792, guided by the crew of the little pinnace (a small ship’s boat) he had sent ahead, Gray brought the 'Columbia' through the breakers of the bar and into the mouth of the legendary "River of the West", which he renamed the Columbia for his ship. After his return to Boston in July 1793, he spent the rest of his career commanding merchant vessels along the Atlantic Coast. He died in July 1806 and was buried at sea.

Gray's discovery of the Columbia River gave the U.S. a strong claim to the contiguous area. By the end of the century traders firmly established a presence on the Washington and Oregon areas of the Pacific Northwest, on which the U.S. would later base its claim to possession.