Almost any organizer planning an event will tell you that participation and funding are of utmost importance in order to encourage success. John Brown had participants for his Harpers Ferry Raid (although he certainly wished for more), and thanks to six principal Northern men, he had a source of financial funding and moral support. These men had given money and arms to Brown while he was waging his antislavery war in Kansas, and Brown readily sought them (and their money) out before his planned raid on Harpers Ferry.
Who were these so called "Secret Six?" All were noted abolitionists, and five of them had connections to the New England Transcendentalist movement. Two were or had been ministers, one was a wealthy businessman, another was a millionaire heir, and two were respected academics.
The lone non-New Englander was 62 year-old Gerrit Smith. Over his lifetime Smith ran the full spectrum of antislavery. At one time he was a committed colonizationist, but over the 1840s and 1850s he had developed into immediate abolitionist. Smith had inherited millions of dollars in script and land from his father Peter Smith, who had been in business with John Jacob Astor. Gerrit Smith had given much of his land in up-state New York (North Elba) to freed and escaped slaves for homesteads. In fact, the Brown family had moved there in the late 1840s. After Brown's successful 1858 raid into Missouri that brought eleven slaves out of bondage, Smith was impressed and provided Brown with additional much needed funds. In the aftermath of Harpers Ferry, Smith would destroy his correspondence with Brown in order help distance himself from the event and had himself committed to an lunatic asylum for a time.
57 year-old Dr. Samuel Gridley Howe had by the time of Harpers Ferry Howe led an interesting life. He had served as a surgeon in the Greek Revolution in the 1820s, and had become involved in antislavery work in the 1840s. He was married to Julia Ward, who would later write the "Battle Hymn of the Republic," based on the tune to the song "John Brown's Body." Howe had funded antislavery efforts in Kansas during the 1850s, but he had opposed the use of violence and was lukewarm at best on Brown's plans for Harpers Ferry. After the event Howe fled to Canada and published a disclaimer of his involvement with Brown.
48 year-old Unitarian minister Theodore Parker was involved in almost every reform movement in the 19th century. He was an advocate for temperance, women's rights, penitentiary reform, and public education. He was vocally adamant against slavery and strongly encouraged slave insurrections. He had provided funds and arms for antislavery forces during the Bleeding Kansas wars, and had become convinced that violence was the proper response and cure for the institution of slavery. Parker had left America in February of 1859 to recuperate from a health breakdown related to tuberculosis, but continued to support Brown. Parker later published a letter titled "John Brown's Expedition Reviewed." Parker died in Italy in May of 1860 from tuberculosis.
36 year-old Thomas Wentworth Higginson like Parker had been a minister, but had been forced to resign by his church for being too radically liberal in his views in the 1840s. Higginson had traveled to Kansas and participated in antislavery activities there in the 1850s before returning to Boston and continuing his work as a writer there. Higginson had urged Brown to undertake his Harpers Ferry plan almost a year before it actually happened and was the only "Secret Six" member who did not flee the country and he never denounced Brown's raid or his involvement. In the Civil War he was a colonel of the 1st South Carolina Colored Infantry.
49 year-old George Luther Stearns was a wealthy factory owner that had met Brown and immediately took to him "like iron to the magnet." Stearns provided both arms and money to Brown. While visiting with Stearns in Boston, Brown became friends with Stearns's young son, to whom Brown wrote a fascinating autobiographical letter. Stearns too left the United States for Canada after the raid was put down, but he remained proud of his involvement with and support for Brown. During the Civil War Stearns helped raise black troops for the Union army.
28 year-old Harvard educated Franklin Sanborn was a Boston-area teacher (Emerson's children were among his students) and secretary of the Massachussetts State Kansas Committee. Sanborn had introduced Brown to Parker and Higginson, and had pledged allegiance to Brown and his cause, often providing financial (sometimes very small amounts) support and moral encouragement through letters to Brown. In 1885 Sanborn published a Brown biography; The Life and Letters of John Brown.
These six men certainly helped Brown's Harpers Ferry plan unfold. Without their support of arms and money it is likely that Brown could not have kept his small army fed, clothed, and armed. While in later years some of the six felt remorse for their support and Brown's use of violence, others cherished and reveled in their association with Brown and their role in helping bring on the Civil War and the conflict that helped begin the end of slavery in the United States.