Chile's interest in expanding into the islands of the Pacific Ocean dates to the presidency of José Joaquín Prieto (1831-1841) and the ideology of Diego Portales, who considered that Chile's expansion into Polynesia was a natural consequence of its maritime destiny. The first stage of the country's expansionism into the Pacific began a decade later, in 1851, when—in response to an American incursion into the Juan Fernández Islands—Chile's government formally organized the islands into a subdelegation of Valparaíso. That same year, Chile's merchant fleet briefly succeeded in creating an agricultural goods exchange market that connected the Californian port of San Francisco with Australia, renewing Chile's economic interest in the Pacific. By 1861, Chile had established a lucrative enterprise across the Pacific, its national currency abundantly circulating throughout Polynesia and its merchants trading in the markets of Tahiti, New Zealand, Tasmania, and Shanghai; moreover, negotiations were also made with the Spanish Philippines, and altercations reportedly occurred between Chilean and American whalers in the Sea of Japan. This period ended as a result of the Chilean merchant fleet's destruction by Spanish forces in 1866, during the Chincha Islands War.