In 1652 Blondel became the tutor of the son of the Secretary of State for foreign affairs, Loménie de Brienne, with whom he made the Grand Tour : Langres — Besançon — Basel — Alsace (Brisach) — Strasbourg (where he inspected the mechanism of the famous clock) — Philippsburg — Mannheim — Mayence — The Hague — Hamburg — Lübeck — Kiel — Denmark — Sweden (Stockholm, Uppsala) — Finland — Estonia (Riga) — Königsberg — Dantzig — Cracow — Pressburg — Vienna — Prague — Vence — Rome — Florence — Toulon. His travels would stand him in good stead when he came to compile his "Cours d'Architecture". During the 1660s Blondel made a second tour with a son of Jean Baptiste Colbert, of which the itinerary is less known.