1448 - Giovanni Leardo, Mapa mondi (left corner); Figura mondi (right corner). Dated and signed: Johanes Leardus de Venetteis me fecit ab ano domini 1448. In Venetian dialect, east orientation, centered on Jerusalem, 34,7 × 31 cm, map diameter 21,4 cm.
Vicenza, Biblioteca Civica Bertoliana, ms. 598ª.
Courtesy of the Biblioteca Civica Bertoliana. Reproduction prohibited.
A cartouche in the author’s hand on the lower edge of the parchment describes the structure of the work and explains how to determine whether Easter falls in March or April from 1448 to 1494:
“Johanes Leardus de Venetteis me fecit ab ano domini 1448. | Per il mapamondo sopra schritto si po vedere chome la tera e le ixole stano nel mare. E molte provinzie e monti e fiumi prenzipali sono nela tera. El diamitro de la tera | siè meia 6857 6/7 segondo Machobrio ecelentissimo astrologo e geumetricho. L’aqua zirconscrisse la tera. El diamitro de l’aqua siè meia 14796. El diamitro | de l’aria siè meia 71429 1/7. El diamitro del fuogo siè meia 68191 2/7. El primo zircholo che zirconscrisse il sopra schrito mapamondo siè dela raxon de la Pasqua per | ani 47. Chomenza nel 1448 al 24 de marzo. Chonpie nel 1494 a dì 30 marzo. Quando se trova letera M ne le chaxelle quel ano la Pasqua vien de marzo; quando | se trova letera A quel ano la viene d’aprille; quando se trova letera B quel ano abiamo bixestro. El segondo zirchulo siè dei 12 mexi de l’ano. El terzo zircullo | siè de 19 letere de l’alfabeto per trovar la raxon de la Luna. Chalculada per senpre. El quarto zirchulo siè de i numeri de’ zorni di mexi. El quinto siè de le hore. | El sesto siè de’ ponti. Poniamo voler sapere quando rinnova la Luna de mazo del 1448. In tal mileximo abiamo chonchorente letera R doncha schoremo | al mese de mazo e trovemo letera R, a l’ingiro troveremo a dì 4 a ore 7 a ponti 424, e a tanti dì a tante ore a tanti ponti renoverà la Luna. Nel 1449 averemo letera S. | Nel 1450 averemo letera T e nel 1451 averemo letera A e chosì se va dredo ogni ano schorendo una letera l’ano de questa raxone. Chomenza | de zenaro e ’l dì chomenza a lo levar del sole. L’ora su ponti 1080 . Quando se trova una letera 2 fiade in un mexe la Luna rinnova do fiade quel mexe”.
English translation:
“Giovanni Leardo of Venice made me in the year of our Lord 1448. From the world map drawn here one can see how the lands and islands are configured with respect to the sea. And the location of many provinces, mountains, and principal rivers. According to Macrobius, most excellent astrologer and geometer, the diameter of the earth is 6,857 and 6/7 miles. [The sphere of] water circumscribes the land. The diameter [of the sphere] of water is 14,796 miles. The diameter [of the sphere] of air is 71,429 and 1/7 miles. The diameter [of the sphere] of fire is 68,191 and 2/7 miles. The first circle that circumscribes the world map drawn here is the calendar o Easter for 47 years. It begins March 24, 1448. It ends March 30, 1494. When the letter M appears in the box, that year Easter falls in March. When the letter A is fund, that year it falls in April. When the letter B is fund, that is a leap year.
The second circle indicates the 12 months of the year. The third displays 19 letters of the alphabet to find the phases of the moon. Calculated forever. The fourth circles displays the number of days in each month. The fifth shows the hours. The sixth shows the minutes. Say we want to know the day of the new moon in May, 1448. The letter R corresponds to that year, so we track to the month of May and find the position of the letter R in correspondence to day 4 and hour 7, 424 minutes, and thus we know that the new moon will appear that day, at that hour, and at those points. In 1449 we will have the letter C. In 1450 we will have the letter T and in 1451 the letter A, and in this way we will track every year with a letter for every year. It begins in January and the day begins with the rising sun. An hour is 1080 minutes. When a letter is found twice in the same month, the new moon in that month will appear twice.”