Several of the men who left Boston for Hawaii in the fall of 1819 had been classmates at a mission school in Cornwall, Connecticut. A fellow student there was Henry Opukaha'ia — called "Obookiah" — the first Hawaiian convert to Christianity. He had left his native land in 1808 aboard a merchant vessel. Once in the United States, he trained to become a minister. He shared stories of the people of Hawaii, describing them as heathens who practiced idol worship and were prey to the loose morals of the European sailors who had been visiting their tropical islands for the past century.

Before Henry Obookiah had a chance to carry his Christian message home, he fell ill and died. In 1818 a memoir of his life became a bestseller among evangelical New Englanders; many readers were moved to help realize his dream of a Christianized Hawaii.

Most people were satisfied to raise funds or contribute money for the new mission, but a small number of men and women sought to go to the islands as missionaries. Because the Boston-based American Board of Commissioners for Foreign Missions (ABCFM), which sponsored the Hawaiian mission, initially required all missionaries to be married, some serious matchmaking was required. In the month before they were to sail, four weddings took place in various Massachusetts towns. In each case, the newlyweds had not known each other before they heard of the proposed mission, but all were committed to the cause and confident that their matches were the result of divine intervention.

The family, friends, and supporters who gathered on the wharf that October afternoon knew it was unlikely they would ever see their loved ones again. At the end of their 18,000-mile journey, the missionaries were expected to become permanent residents of Hawaii — indeed, they were required to give up their U.S. citizenship to settle there. If they were successful in their work, they would spend the rest of their lives unimaginably far from home. Their charge from the ABCFM was daunting: "You are to aim at nothing short of covering those islands with fruitful fields and pleasant dwellings, and schools and churches; of raising up the whole people to an elevated state of Christian civilization."

The voyage was difficult. The ship was cramped, the missionaries were seasick, and by the middle of the trip, four of the wives were pregnant. The couples spent as much time as they could learning the Hawaiian language and sharing tales of missionary successes in other "heathen lands."

In late March of 1820, after five months at sea, the big island of Hawaii came into view. The missionaries were shocked by their first encounters with the native people. When the Thaddeus anchored, the ship was greeted by men and women of all ages, some surfing, others sailing, and others dancing or running along the shore.

The missionaries set to work building New England-style frame houses and a church, creating a reading primer in Hawaiian and translating the Bible and other texts into the native language, setting up schools, preaching Christian teachings, and providing basic medical care. The Hawaiians were accustomed to going without clothing and to gathering their food and fish from the wild. They were completely uninterested in most things the Americans considered important, chiefly farming, sewing, and cooking, but with traditional Hawaiian religion already in decline, the missionaries made headway in spreading Christianity.

Over the next 30 years, another 180 men and women of various Christian denominations would come to Hawaii as missionaries. Of the first group, one couple stayed seven years, another 15; a few spent the rest of their lives in Hawaii.