Dr. Samuel Bard built a house at Hyde Park in 1795, the first to stand on the site of Vanderbilt Mansion. A large house on the high elevation rising about 300 feet above the Hudson, it commanded a superb view of the river and of the mountains beyond. A garden was laid out on the land west of the Albany Post Road, and by 1820 a greenhouse, said to have been the first one in Dutchess County, was erected. In addition to his interest in trees and improvement of the grounds, Dr. Samuel Bard undertook experiments in horticulture and farming. He imported fruits from England, France, and Italy, and vines from Madeira. The Society of Dutchess County for the Promotion of Agriculture made him its first president in 1806. In this position he encouraged the use of clover as a crop and gypsum as a fertilizer. Dr. Samuel Bard lived at Hyde Park until his death in 1821 at the age of 79. His death followed within 24 hours that of his wife, Mary. [Illustration: _Map of the Hyde Park Patent, about 3,600 acres, showing land sales made by Dr. John Bard and Dr. Samuel Bard. In the time of Vanderbilt the estate comprised approximately the tracts labeled “Dr. David Hosack” and “Magdalene Hosack.” The National Historic Site comprises the land owned by Vanderbilt west of the Post Road and fronting the Hudson River._] [Illustration: _Walter Langdon, Jr._] Their only surviving son, William Bard, inherited Hyde Park which had been reduced by land sales to 540 acres. He lived there only until 1828, when he sold the estate to Dr. David Hosack of New York City. A former professor of natural history at Columbia College, Dr. Hosack had become a partner of Dr. Samuel Bard and had taken over the latter’s medical practice when he retired. Dr. Hosack spent vast sums of money for the improvement of his property. He was to create the first of the great Hudson Valley estates. Deeply interested in botany, he revived horticultural experimentation and gardening at Hyde Park. Many of the rare specimens that today grace the lawns and gardens probably date from the period immediately following Dr. Hosack’s acquisition of the estate. Andre Parmentier, a Belgian landscape gardener, was engaged to lay out roads, walks, and scenic vistas. In 1829, under the guidance of Martin E. Thompson of the architectural firm of Town and Thompson, Dr. Hosack remodeled and enlarged the house built by Dr. Samuel Bard in 1795. A new carriage house and gate lodges were also designed and constructed.