From the period of these publications, the Grand Duke, entertaining a high opinion of Lanzi's judgment, was in the habit of consulting him before he ventured to add any new specimens to his cabinet of antiquities. He was also entrusted with a fresh arrangement of some new cabinets belonging to the gallery, which together with the latter, he finally completed, on a system which it is said never fails to awaken the admiration of all scientific visitors at Florence. During this task, his attention had been particularly directed to the interpretation of the monuments and Etruscan inscriptions contained in the ducal gallery, which, together with the ancient Tuscan, the Umbrian, and other obsolete dialects, soon grew familiar to him, and led to the composition of his celebrated _Essay upon the Tuscan Tongue_. For the purpose of more complete research and illustration, he obtained permission from the duke to visit Rome, in order to consult the museums, and prepare the way for his essay, which he published there in 1789; a work of immense erudition and research. It was here Lanzi first appeared as the most profound antiquarian of modern Italy, by his successful explanation of some ancient Etruscan inscriptions and remains of art, which had baffled the skill of a number of his most distinguished countrymen. Upon presenting it to the grand duke, after his return from Rome, Lanzi was immediately appointed his head antiquary and director of the Florentine gallery; while the city of Gubbio raised him to the rank of their first patrician order, on account of his successful elucidation of the famous Eugubine Tables. In one of his _Dissertations upon a small Tuscan Urn_, he triumphantly refuted some charges which had been invidiously advanced against him, and defended his principles of antiquarian illustration by retorting the charge of fallacy upon his adversaries. In the year 1790, Lanzi, at the request of the Gonfaloniere and priors of Monte dell'Olino, published an inquiry into the _Condition and Site of Pausula, an ancient City of Piceno_; said to be written with surprising ingenuity, yet with equal fairness; uninfluenced by any prejudices arising from national partiality, or from the nature of the commission with which he had been honoured. This was speedily followed by a much more important undertaking, connected with the prosecution of his great design, which it would appear he had already for some time entertained.