Beginning of the construction of the Renaissance's castle

In September 1519, after the abandonment of a grand urbanistic and hydraulic project for the city of Romorantin, at the  time of as Leonardo da Vinci's death, Francis I launches the construction of a "bel et somptueux √©difice" on the site of a former castle surrounded by marshes and woods. The archives give precision neither on the conception and the aim nor the architect of this project.