Chronology
1926 Members of the Threefold Group purchase property on Hungry Hollow Road and start Threefold Farm.
1929-1933 Major renovations are undertaken to make the property into a working conference center. The original farmhouse (today known as Main House) is made into a guesthouse and restaurant, and the original cow byre (today known as Brookside) is converted into a lecture hall.
1933 The first Anthroposophical Summer Conference is held in July. Except for the World War II years, summer conferences have been held every year since 1933.
1946-1961 Ehrenfried Pfeiffer lives and works at Threefold, teaching, consulting and conducting research in agriculture and food quality.
1948 First year of the Kindergarten that eventually evolves into Green Meadow Waldorf School.
1949 Threefold Auditorium is dedicated.
1950's Construction of a studio for the painter Richard Kroth; that building today houses Eurythmy Spring Valley.
1956 Green Meadow Waldorf School opens its first building (today’s Kindergarten), and inaugurates elementary education.
1965 The Threefold Educational Foundation and School is chartered, and various property holdings and legal entities are consolidated under its umbrella.
1966-1974 Continued Green Meadow expansion: Construction of the Lower School in 1966, the Gym in 1970, the Arts Building in 1973, and the High School in 1974.
1966 The Rudolf Steiner Fellowship Foundation, a community-based retirement facility, is chartered by the New York State Department of Social Welfare.
1970 An international youth conference, "Self Development and Social Responsibility," draws 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.
1980 Dorothea Mier arrives to re-found Eurythmy Spring Valley.
1986 The Waldorf Institute relocates to Threefold and is renamed Sunbridge College.
1986 The Village of Chestnut Ridge is incorporated.
1990-2000 Ongoing work to upgrade properties and bring them into compliance with new zoning regulations.
1991 Sunbridge College is authorized to grant the Master of Science degree.
1990-1991 Construction of Holder House, a 40-room dormitory for students of Sunbridge College and Eurythmy Spring Valley.
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 Gunther Hauk arrives to found The Pfeiffer Center for Biodynamics and the Environment.
2004 Renovation and expansion of the Co-op includes construction of a 3,000 square foot rain garden.
2005 Dorothea Mier retires and Barbara Schneider-Serio takes on Directorship of Eurythmy Spring Valley.
2005 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.

Threefold Farm

Biodynamic gardening

Tea time

Ehrenfried Pfeiffer

The 1940 Summer School

Threefold Auditorium

Green Meadow

The Fellowship

Eurythmy Spring Valley

Gunther Hauk