A great portion of the duchy of Urbino, including its principal towns, has been thrice visited, and nearly every accessible library of Central Italy has been examined for unedited matter. To these researches, time and labour have been freely given; and in the few instances when his attempts were foiled by jealousy or accident, the author has generally had the satisfaction of believing that success would have been comparatively unproductive. To this, two exceptions should be mentioned. He was prevented by illness from recently visiting the libraries or archives at Venice; and the Barberini Library at Rome has been entirely closed for some years, in consequence of a disgraceful pillage of its treasures. Should the latter be again made accessible, the MSS. amassed by the Pontiff under whom Urbino devolved to the Church, and by his nephews, its two first Legates, can hardly fail to throw much light upon the duchy. The invaluable treasures of the Vatican archives have been to him, as to others, a sealed book; but the Urbino MSS. in the Vatican Library, those of the Oliveriana at Pesaro, and of the Magliabechiana at Florence, have afforded copious sources of original information, and have supplied means for rectifying omissions and errors of previous writers. Some of these materials had been freely drawn upon by Muzio, Leoni, and Baldi, biographers of the early dukes of Urbino, who have not, however, by any means exhausted the soil; the amount that remained for after inquirers may be estimated from the single instance of Sanzi's almost unnoticed rhyming Chronicle of Duke Federigo, in about 26,000 lines. The reigns of Dukes Federigo, Guidobaldo I., and Francesco Maria I., from 1443 to 1538, formed the brightest era of Urbino, and included the most stirring period of Italian history, the golden age of Italian art; but our regnal series would be incomplete without Dukes Guidobaldo II. and Francesco Maria II., who prolonged the independence of the duchy until 1631, when it lapsed to the Holy See. Its history thus naturally divides itself into five books, representing as many reigns; yet, as these sovereigns were of two different dynasties, it will be convenient to consider separately the origin of each, and the influence which they respectively exercised on literature and the fine arts, thus giving matter for four additional books. In Book First of these we shall briefly sketch the early condition of the duchy, with the establishment of the family of Montefeltro as Counts, and eventually as Dukes, of Urbino; but, regarding Duke Federigo as the earliest of them worthy of detailed illustration, we shall, in Book Second, with his succession, enter upon the immediate scope of our work. * * * * *