When originally constructed in 1875 for Henri Braem, U.S. Ambassador to Denmark, the estate was given the name Ethelwynde. Eighteen years later, the property became the country retreat for the family of Mrs. Katharine Wilson Taylor Winthrop. Mrs. Winthrop was a renowned gardener and botanist whose specimen plantings still grace the property. She hosted what the New York Times called some of "the definitive parties of the season" and was the daughter of Moses Taylor, one of the great railroad, iron and coal financiers of the 19th century and the first president of City Bank (now Citicorp). Her husband was Robert Winthrop, direct descendant of Massachusetts founding Governor John Winthrop and a significant financier and political figure in his own right. The association with the Winthrop family is why the Ethelwynde estate has become well-known as Winthrop Estate.
In 1925, the Winthrop family sold the property to Halstead Lindley, who embarked on building a new home for his wife, Emily Low Bacon of Boston, who had summered in Lenox throughout her childhood. Mr. Lindsley was a mining engineer by training and was the founder and owner of some of the largest copper, nickel, silver and gold mines in the world. He replaced the original wood-framed house, with a grander home built from Weymouth Granite based on English precedents with hand-carved marble fireplaces, multi-layered dental molding in the formal dining room, a proper conservatory, and numerous bedrooms. Mr. Lindsley commissioned fixtures, made of solid nickel from his mines, which remain in place in the mansion. He installed the library woodwork using rare Purpleheart logs that were floated up the Amazon River by one of his mining companies. Mr. and Mrs. Lindsley made the estate their summer home until the middle of the 1940s.
After Mr. Lindsley passed away, the estate was sold in 1948 to Isabella Hunnewell Dexter. She was a member of the prominent Boston-based Hunnewell family who were well-known important horticulturists and Boston philanthropists. One can imagine she was particularly attracted to the estate's landscape and stunning views as they reminded her of her family's Boston area estates. She was married to Gordon Dexter, a direct descendant of John Singleton Copley and she donated several of Copley's portraits to the National Gallery in Washington D.C.
The property was then owned by Mr. Chester Hammond, president and chairman of the H.F. Livermore Corporation, who bought it for his mother. It was sold again in 1954 to Sally Schieffelin, widow of Mr. George Schieffelin, who was president of the Schieffelien Liquor Conglomerate. She was known for her Pekinese dogs, and her support of the Lenox Library. Her trust continues to provide annual donations to the Lenox Library today. In 1976, Dr. Milos Krofta, president and founder of the Krofta Engineering Corporation of Lenox, purchased the estate to use as the international headquarters of his water purification firm, Krofta Waters.
In 2003, the estate was purchased by Ethan and Jamie Berg who embarked on a multi-year restoration of the building and especially the grounds. While it has been primarily used as a private family retreat, it has also been the home of The Lenox Athenauem, hosting musical recitals including musicians such as Yo Yo Ma and Emanuel Ax, book authors including Simon Winchester, and events such as TEDxBerkshires. The estate is a unique combination of 45 acres of privacy and extreme proximity to both the center of Lenox and Tanglewood.