1923 The Threefold Commonwealth Group forms in New York City. Led by Ralph Courtney, members include Gladys Barnett (later Hahn), May Laird-Brown, Louise Bybee, and Charlotte Parker. Not the first group of anthroposophists in New York, the Threefold Group soon becomes the most active and lively.
1924 The Threefold Group operates a rooming house, a laundry, a furniture-making shop, and a vegetarian restaurant near Carnegie Hall.
1926 Ralph Courtney, Charlotte Parker, Gladys Barnett (later Hahn), Louise Bybee, Margaret Peckham, Alice Jansen, and Reinhardt Mueller – on behalf of the Threefold Group – buy the property in Spring Valley, NY, and name it Threefold Farm. Biodynamic farming begins immediately, to supply the Threefold Vegetarian Restaurant in New York City.
1929-33 Major renovations are undertaken to make the property into a working conference center and summer retreat. The cow byre becomes first an office, and eventually a lecture hall today known as Brookside. Main House is expanded to provide guest rooms and dining facilities.
1933 The first Anthroposophical Summer Conference takes place on July 8-23. Within a few years, the “Summer Season” of activities runs from early June to Labor Day, with a Summer School running for three weeks in July. Except for two years during World War II, summer conferences have been held every year since 1933.
1943-73 Threefold Dairy operates on Red Barn Lane under the guidance of Ernst and Margaret Daniel.
1946-61 Teacher, scientist and biodynamic pioneer Ehrenfried Pfeiffer, who taught at the first Summer Conference in 1933, founds his Biochemical Research Laboratory at Threefold in 1946. He lives and works at Threefold until his death in 1961.
1948 First year of the kindergarten that eventually evolves into Green Meadow Waldorf School.
1949 The summer conferences get their first permanent indoor home when Threefold Auditorium is dedicated. Mieta Waller-Pyle, Daniel Birdsall, Ralph Courtney and Carl Schmidt collaborated on the auditorium’s design and construction. From its dedication until 1974, the auditorium also housed the research laboratory of Ehrenfried Pfeiffer.
1950s Work with Rudolf Steiner’s mystery dramas begins when Hans and Ruth Pusch form the Threefold Mystery Drama Group.
  Construction of a studio for the painter and Threefold community resident Richard Kroth. Today this building is the home of Eurythmy Spring Valley.
1956 Green Meadow Waldorf School opens its first building (today’s Kindergarten), and inaugurates elementary education.
1959 Paul and Ann Scharff, co-founders of the Fellowship Community, arrive at Threefold and begin work to establish the Rudolf Steiner Fellowship Foundation.
1965 In the last year of his life, Ralph Courtney leads the initiative to charter the Threefold Educational Foundation and School, uniting the community’s various properties and legal entities.
1966 The Rudolf Steiner Fellowship Foundation receives a charter from New York State to create the Fellowship Community, an intentional community centered around the care of the elderly. The Monges family’s Hill Top House, designed by Walter Leicht, becomes the Fellowship’s main residential and dining facility.
1966-74 Green Meadow opens its Lower School (1966), Gym (1970), Arts Building (1973), and High School (1974). These and many other community buildings were designed by Walter Leicht, who also managed Threefold maintenance and construction for many years as a volunteer while maintaining a large private practice.
1970 “Self Development and Social Responsibility,” an international youth conference, draws some 600 participants from throughout the U.S. and Europe.
1972 Lisa Monges begins a training in eurythmy later to become Eurythmy Spring Valley.
1973 The Hungry Hollow Co-op begins operations as a natural foods buyers’ club from the basement of a Green Meadow teacher’s house.
Green Meadow holds its first 12th grade graduation.
1976 Eurythmy Spring Valley graduates the ‘A’ course, its first class of full-time students.
1980 Dorothea Mier, pictured above directing a rehearsal, arrives to re-found Eurythmy Spring Valley.
1986 The Eurythmy Spring Valley Ensemble embarks on its first performance tour.
Under the leadership of Werner Glas, the Waldorf Institute of Detroit relocates to Threefold and later takes the name Sunbridge College.
The Threefold campus and surrounding neighborhood is included within the newly incorporated Village of Chestnut Ridge.
Ed Bieber founds The Nature Place, an innovative noncompetitive day camp, using the Threefold and Green Meadow campuses.
1990-91 Construction of Holder House, a 40-room dormitory for students of Sunbridge College and Eurythmy Spring Valley.
1990-2000 Ongoing work to upgrade properties and bring them into compliance with new zoning regulations.
1990-2006 Teacher and researcher Norman Davidson delivers annual Advent Star Talks that synthesize his astronomical studies and his spiritual scientific research into the relationship between humanity and the cosmos.
1991 Sunbridge College is accredited by New York State to grant the Master of Science degree.
1993 The Hungry Hollow Co-op Natural Foods Market opens its doors to the public in its new location at the corner of Hungry Hollow and Chestnut Ridge Roads.
1996 Renate Hiller and Michael Howard begin the Sunbridge College Applied Arts program.
Gunther Hauk arrives to found the Pfeiffer Center for Biodynamics and the Environment.
The Fellowship Community acquires neighboring Duryea Farm, converting it to biodynamic practices and establishing the only dairy in Rockland County.
2005 Dorothea Mier retires and Barbara Schneider-Serio becomes the director of Eurythmy Spring Valley.
Internal re-organization of the Foundation; a conceptual Master Plan for the property is developed and adopted.
2007 Mac Mead takes on leadership of the Pfeiffer Center.
2008 Sunbridge College’s Applied Arts program becomes the Fiber Craft Studio, operating under Threefold Educational Foundation.
2008-13 Starting with a conference to honor Henry Barnes and mark the 75th anniversary of the first Summer School at Threefold Farm, Threefold Educational Center conducts six annual Michaelmas conferences on spiritual scientific research.
2010 The Otto Specht School, which provides Waldorf education to children with learning differences, begins operating under the charter of Threefold Educational Foundation.
2010-15 Responding to changing needs, Sunbridge College re-imagines itself as Sunbridge Institute, focusing on low-residency programs for aspiring and practicing Waldorf teachers. A Masters program in partnership with Empire State College is announced.
2011 The Seminary of the Christian Community in North America, founded in Chicago in 2001, relocates to the Threefold community.
2014 In August, a nine-day festival and conference celebrates Rudolf Steiner’s four mystery dramas. Threefold Mystery Drama Group performs all four plays in repertory in English, a historical first.

Threefold Farm

Biodynamic gardening

Tea time

Ehrenfried Pfeiffer

The 1940 Summer School

Threefold Auditorium

Green Meadow

The Fellowship

Eurythmy Spring Valley

Gunther Hauk