The Heintzman House (circa 1817), also known as Sunnyside Manor Farm, is one of the oldest buildings in Thornhill- Markham, and has one of the most interesting histories of any building in the area. The earliest mudhouse on record in the province, the house is constructed of adobe brick, fired brick and frame construction. The central five bays are the oldest portion of the house, which includes the adobe brick construction.The Yonge Street Crown Grant property (Lot 32, Concession 1, Markham) was awarded to United Empire Loyalist, Anthony Hollingshead in July of 1798. Hollingshead, originally from New Jersey, was a veteran of the American Revolutionary War, serving as an officer with the 3rd New Jersey Volunteers under the command of General Courtland Skinner.Prior to receiving the patent (final property deed), Crown Grant recipients had to complete settlement duties which included clearing land for cultivation, building a home no less than 16 feet by 20 feet in size, and clearing the land facing Yonge Street for use as a public road. Settlers were given two years to complete their duties, extensions were often granted. Anthony, his wife Elizabeth, son Anthony Jr., including a daughter, her husband and child all made their home in a modest two- room, one-half storey adobe brick farmhouse. Portions of the adobe farmhouse are believed to have been incorporated into the existing house, which has seen several additions and changes over the past many years. Anthony Hollingshead received the patent (deed) to the 190-acre property in 1802 after completing his settlement duties.In 1817, possibly upon the death of Anthony, the Hollingshead family sold the property. Based on land registry records, the second owner was the Honourable George Crookshank of York (Toronto). George, the son of a Loyalist, was a prominent member of Upper Canada society devoting much of his professional career to government service. Crookshank, a trusted friend and confidant of Lieutenant Governor John Graves Simcoe, would hold many important positions; Assistant Commissary General in 1796, Receiver General of Public Accounts 1819, Director of the Bank of Upper Canada in 1822 and would serve as a member of the Legislative Council between 1821 to 1841.Crookshank, a man of great wealth, spared no expense in building a 13-room mansion on the site of the Hollingshead farmhouse. The black walnut wood paneling and moulding seen throughout the house dates to this period and was milled from trees harvested from the estate. In 1859, upon his death at 86 years of age, George Crookshank was remembered for his staunch Loyalists beliefs, his generous nature and charitable activities. Catherine Crookshank Hewerd, his only surviving child, inherited not only the Thornhill estate but also vast tracts of property in the city of Toronto.The farm property, known as Sunnyside Manor, would pass through many hands until purchased in 1881 by John Francis of Newtonbrook. Sons Samuel and Elijah were set up on the property as farmers; Elijah would eventually sell his share of the property to his brother Samuel and move to England.Charles Theodore Heintzman and his wife, Marion, purchased Sunnyside Manor in 1930 from Samuel Francis for the reported amount of $ 100,000. Charles, the son of Herman and Lucy Heintzman, was the grandson of Theodore A. Heintzman, founder of the Heintzman Piano Company of Toronto. Charles was born in Toronto and educated at St. Andrews College; after graduation he served his apprenticeship in the family's piano manufacturing business. Charles would eventually become a director and by 1950 became a vice president of the company.Charles was a keen outdoors man, and both of the Heintzmans were interested in farming and kept a herd of prized Jersey cattle on their Thornhill property. Mr. and Mrs. Heintzman added the pillars and portico as well as the conservatory, a garage and servants quarters, taking care that these and other alterations would preserve the character and unique features of the house.Charles Heintzman died at his beloved Sunnyside Manor in September of 1954; Marion Heintzman died within a few years of Charles' death. In 1959 Sunnyside Manor was sold to real estate developers for the reported amount of $880,000.There was a concern that the developers were planning on demolishing the house to make room for a high-rise apartment. Residents in the area, led by Alan Sumner, opposed the plan and launched a campaign to save Sunnyside Manor and were successful in convincing the Town of Markham to purchase the property in 1966.The house was renamed Heintzman House in honour of the last private owner and was, for a time, used as offices for the Town of Markham Recreation and Parks Department and as a community center. In 1984 the Heintzman House received designation as a heritage site under the Ontario Heritage Act.In May of 2000, the Heintzman House was honoured by the United Empire Loyalists' Association of Canada with a special presentation of the First Union Flag in honour of the property's first owner, United Empire Loyalist, Anthony Hollingshead. Only two other properties in the greater Toronto area have received such an honour - Fort York and Queen's Park.The presentation was made in recognition of Anthony' s participation in the Battle of the Blockhouse at Bergen Wood, N.J., (July 1780), an important Loyalist victory during the closing days of the American Revolutionary War. British Commander Sir Henry Clinton, in a dispatch to Whitehall, England, described the battle as "an instance of courage which reflects the great honour of a small body of refugees (Loyalists)."The Hollingshead clan held a family reunion at the Heintzman House in July 2000. Meeting their Canadian cousins for the first time were the American great great grandchildren of Elizabeth and Samuel Lount. Elizabeth Soules Lount, granddaughter of Anthony and Elizabeth Hollingshead, was forced to flee to the United States following the execution of her husband, Samuel, for his role in the Upper Canada Rebellion of 1837. (See story-The Liberal, July 25, 2000)A group which has played a prominent role in the recent history of the house is the Heintzman House Auxiliary. Many of the original members of the Auxiliary were involved in the campaign to save the house from demolition. Since 1971, the Auxiliary volunteers have organized an annual craft show fundraiser with proceeds going to the refurbishment of the house.Today, a Board of Directors appointed by the Town of Markham manages the Heintzman House. The house is rented by local organizations, used for business meetings, has been used in commercial and film work, and is a popular venue for wedding parties and receptions.Heintzman House Auxiliary (2003)Special thanks to the Hollingshead family for their help in compiling the history of the property.