His chief minister, the Cardinal de Richelieu, added another important building in the centre of Paris. In 1624, he started construction of a grand new residence for himself, the "Palais-Cardinal", now known as the Palais-Royal. He began by buying several large mansions located on the Rue Saint-Honoré (next to the then still-existing Wall of Charles V), the (first) Hôtel de Rambouillet and adjacent Hôtel d'Armagnac, then expanding it with an enormous garden (three times larger than the present garden), with a fountain in the centre and long rows of trees on either side.[60]