These fragments of what seems to have been Leto's field notebook contain his notes on an inscription including an ancient Roman calendar on stone. This calendar depicted the signs of the zodiac through which the sun passed, gave the lengths of days and nights, listed the agricultural tasks and religious festivals appropriate to each month, and provided other important information, like the dates of the solstices and equinoxes. The Roman calendar was complex, sophisticated, and steeped in beliefs deeply rooted in the Roman past. Leto's discovery, now known as the "Menologium rusticum Vallense," was a major addition to the humanists' stock of knowledge about Roman practices and beliefs.
Vat. lat. 3311 fol. 180 verso arch06 TG.05
The "Menologium" that Pomponio Leto copied out was printed in a little brochure in Rome early in the sixteenth century. The printer, Mazzocchi, drew his text from a manuscript collection of inscriptions compiled by one of the most expert specialist antiquaries of the late fifteenth century, Fra Giovanni Giocondo. Though texts like this circulated widely in the age of manuscripts, printing obviously made them accessible to a far larger circle of scholars than scribal efforts could.
Vat. lat. 5234 fols. iii verso-iiii recto of booklet tipped in (fol. 86 recto) arch07 TG.06
Leon Battista Alberti helped Pope Nicholas V draw up the first of many projects to rebuild Rome and studied the work of ancient architects building by building. In this short treatise he describes how to use a mathematical instrument to measure the distances between the most important Roman buildings and to plot them on a circular map. Alberti had seen and been impressed by the maps in the Greek text of Ptolemy's "Geography" and hoped to provide an equally rigorous and quantitative framework for the study of ancient and modern Rome--an enterprise characteristic of the curia.
Chig. M. VII 149 fol. 3 recto arch08 TG.10
Flavio Biondo, papal secretary and historian, reconstructed the physical and institutional textures of Roman life in works that remained standard for a century or more. He reached a large audience through printed editions of the originals and Italian translations. His great compilation "Roma instaurata," displayed here, provided the first systematic and well-documented guide to the ruins of the city. The pages shown describe the Baths of Diocletian.
Vat. lat. 1941 fols. 36 verso-37 recto arch09 TG.12
This panoramic view of Rome may have been the first to use Alberti's method. It was centered on the Monte Mario, behind the Vatican, and locates principally such Christian monuments as Ara Coeli.
Vat. lat. 2224 fol. 98 recto arch10 TG.62