In 1979, French entrepreneur purchased the ruins of the Château de Saint-Fargeau and began restoring it with profits raised on-site. In late 1995, a study by Guyot's staff revealed the medieval foundations beneath the modern, brick structure, complete with a hypothesized plan of the original castle. Guyot built the existing château after some consideration, but began assembling funds and experts and opening negotiations with the French government to build a new castle. Over five months in 1997, Guyot raised €400,000 from the European Union, local and the central French governments, and commercial entities. A former sandstone quarry, located in a woodland two hours south of Paris, was chosen as the site of Guédelon Castle because of its relative elevation and abundance in natural resources, whose transport would be expensive in the Middle Ages. Permission for construction was given by the commune of Treigny on 25 July 1997, and ground was broken the following year with the clearing of the site and the erection of the first workshops. The first stone was laid on 20 June 1997. Over the rest of that year and into 1998, the perimeter was built to a metre (3 feet) in height, following which Guédelon was opened to the public.