Despite accompanying Vasi’s panorama, the Indice istorico was in fact a second edition of his Itinerario istruttivo di Roma antica e moderna (1763). Guidebooks like Vasi’s (this copy is part of the King’s Library) were very popular among Grand Tour travellers, who used them in conjunction with small fold-out maps to navigate Rome’s streets. They contained detailed information not only on streets and squares, taverns and stables, but also on important buildings and monuments, often illustrated, as in this case, with small etchings. Fulfilling a role similar to the cicerone, or hired guide, Vasi escorts his readers around Rome in and eight-day tour that ends with a visit to St. Peter’s. While including all the main sights, the author also promises to lead the discerning tourist to more remote parts of the city, ‘without leaving anything unobserved’, as he explains in his introduction.