Question: Who founded the organization whose Boston branch excluded the Christian discussion group later housed in the Boston Young Men's Christian Union?

Context paragraphs:
Boston Young Men's Christian Association: The Boston Young Men's Christian Association (also known as "YMCA of Greater Boston") was founded in 1851 in Boston, Massachusetts, as the first American chapter of the YMCA.

Samuel Hall Gregory: Samuel Hall Gregory (1814–1892) was an interior decorator and wallpaper manufacturer, importer and retailer in Boston, Massachusetts, in the 19th century.  "He was known for being one of the first 'high society' decorators in America."  He worked in Boston with a succession of business partners: C. Dudley Brown, James H. Foster, S.M. Hurlbert, Charles W. Robinson, and also with T. Christy and S.S. Constant of New York.  In 1852 Gregory served on the board of the newly established Boston Young Men's Christian Association, the first YMCA chapter in the United States.  He worked on Court Street (1840s-1870s) and West Street (1880s) in Boston, and lived in Brookline, Massachusetts.

Durham Inter-Collegiate Christian Union: The Durham Inter-Collegiate Christian Union, usually known as DICCU, is a Christian Union in Durham University and is the University's most prominent student Christian organisation.  It was founded in its present form in 1931, but can trace its roots back in principle to the early 1920s and in name well before that.

Norma Guillard: Norma Guillard Limonta is a Cuban social psychologist and adjunct lecturer at the University of Havana.  She is a co-founder of Grupo Oremi, a now defunct lesbian discussion group in Cuba.  Her academic works borders on gender, sexuality, race and identity.  Guillard is a foundation member of the Cuban branch of La Articulacion Regional de Afrodescendientes de Latinoamerica y el Caribe, a joint regional discussion group composed of individuals of African descent in Latin America and the Caribbean.

YMCA: The Young Men's Christian Association, commonly known as the YMCA or simply the Y, is a worldwide organization based in Geneva, Switzerland, with more than 2 billion beneficiaries from 125 national associations.  It was founded on 6 June 1844 by George Williams in London and aims to put Christian principles into practice by developing a healthy "body, mind, and spirit."  These three angles are reflected by the different sides of the (red) triangle—part of all YMCA logos.

YWCA Boston: The Boston Young Women's Christian Association (YWCA) (est.1866) was founded in Boston, Massachusetts, "to aid the young working-women of Boston, without regard to their religious belief."  It was incorporated in 1867 by Pauline A. Durant, Ann Maria Sawyer, Hannah A. Bowen, and Clara L. Wells.  It is the United States' oldest YWCA.  With a mission to eliminate racism, empower women and promote peace, justice, freedom and dignity for all, the organization has been providing services to Boston residents and visitors for 150 years.

Great Books Foundation: The Great Books Foundation, incorporated in the state of Illinois and based in Chicago, is an independent, nonprofit educational organization whose mission is to help people think and share ideas.  Toward this end, the Foundation publishes collections of classic and modern literature as part of a continuum of reading and discussion programs for children and adults.  The foundation has two main programs: Junior Great Books, serving students in kindergarten through high school, and Great Books Discussion for college students, continuing education, and Great Books book groups.  The organization derives its income from the sale of books, teacher professional development fees, contributions, and grants.

Boston Young Men's Christian Union: The Boston Young Men's Christian Union is an historic building at 48 Boylston Street in Boston, Massachusetts and a liberal Protestant youth association.  When Unitarians were excluded from the Boston YMCA (which was evangelical) in 1851, a group of Harvard students founded a Christian discussion group, which was incorporated as the Boston YMCU in 1852.  In 1873, the organization decided to construct its own building.  $270,000 was raised, and construction on the original segment completed in 1875.  The building was designed by Nathaniel Jeremiah Bradlee, constructed in a High Victorian Gothic style, and included ground-level retail.  Several additions were made, including in 1956.  The building was designated a Boston Landmark by the Boston Landmarks Commission in 1977 and added to the National Historic Register in 1980.  Boston YMCU owned Camp Union, a 600 acre camp, in Greenfield, New Hampshire (1929–1993) (now Barbara C. Harris Camp & Convention Center of the Episcopal Diocese of Massachusetts).  From its renovation in 2003 to 2011 it was called the Boylston Street Athletic Club, and later the Boston Union Gym or BYMCU Athletic Club.

United General Workers Union: United General Workers Union, a central trade union organization in Belize.  Founded in 1979 through the merger of Belize General Development Workers' Union and the Southern Christian Union.  During the 1980s UGWU was seen as the most leftist trade union organization in the country.

Capstone Partners: Capstone Partners, LLC is an independent middle market investment bank, formerly the Boston branch for Arthur Andersen Corporate Finance's M&A group, at that time a wholly owned subsidiary of Arthur Andersen.  The practice was founded in 1996, with John Ferrara as Andersen's Director for the Boston branch.  Following the Enron Scandal of 2001, Capstone Partners spun a core practice out of Andersen and was legally incorporated by the firm's current President John Ferrara in Spring 2002.  Capstone Partners, LLC focuses in M&A and capital markets advisory in the New England region.

Supporting paragraphs: Boston Young Men's Christian Union YMCA
Answer: George Williams