Although he wore a monk’s habit, Fra Mauro (active ca. 1430-ca. 1459/1464) lived as a lay brother in the Camaldolite monastery of San Michele in Isola. His presence in the convent is attested from 1409, and in the subsequent twenty years he distinguished himself principally as a cosmographer. He was responsible for the drafting of topographic maps (charts of the lands held by the Camaldolite monastery of San Michele di Leme, in Istria) and for hydrological projects, such as the deviation of the River Brenta. Beginning in 1448-1449 he dedicated his efforts to creating world maps; the one now preserved in the Marciana Library probably dates from this time.

The Marciana world map is unquestionably his masterpiece. A copy commissioned by Afonso V (1432-1481), king of Portugal, between 1457 and 1459 was sent to Lisbon on April 24, 1459, but has unfortunately been lost. Another copy, in Latin and commissioned by Lorenzo the Magnificent (1449-1492) around 1480, has also regrettably been lost.

Although celebrated during his lifetime as cosmographus incomparabilis, Fra Mauro’s name sank into obscurity shortly after his death sometime between 1459 and 1464. Upon his passing, all his writings, drawings, and world maps were shut up in a chest deposited in the Camaldolite monastery of San Giovanni Battista, on the Venetian island of the Giudecca, where they remained until 1464. After this date the materials were returned to San Michele in Isola, but by the end of the 18th century these precious papers had been scattered. The world map was remembered simply as “the San Michele world map”.