The site of the square was formerly the "hôtel" of César de Bourbon, Duke of Vendôme, the illegitimate son of Henry IV and his mistress Gabrielle d'Estrées. Hardouin-Mansart bought the building and its gardens, with the idea of converting it into building lots as a profitable speculation. The plan did not materialize, and Louis XIV's Minister of Finance, Louvois, purchased the piece of ground, with the object of building a square, modelled on the successful Place des Vosges of the previous century. Louvois came into financial difficulties and nothing came of his project, either. After his death, the king purchased the plot and commissioned Hardouin-Mansart to design a house-front that the buyers of plots round the square would agree to adhere to. When the state finances ran low, the financier John Law took on the project, built himself a residence behind one of the façades, and the square was complete by 1720, just as his paper-money Mississippi bubble burst. Law suffered a major blow when he was forced to pay back taxes amounting to some tens of millions of dollars. With no way to pay such an amount, he was forced to sell the property he owned on the square. The buyers were members of the exiled Condé branch of the House of Bourbon who later returned to the country to reclaim their land in the town of Vendôme itself. Between 1720 and 1797, they acquired much of the square, including a freehold to parts of the site on which the Hôtel Ritz Paris now stands and in which they still maintain apartments. Their intention to restore a family palace on the site was dependent on the possible intentions of the adjacent Justice Ministry to expand its premises.