One of the hundreds of manuscripts lost and found in Toledo. Photograph: Michael Noone

For three years starting in 2000, Michael Noone, associate professor of music, scoured the great cathedral in Toledo, Spain, rummaging through chapels, vaults, choir lofts, and every other niche of the massive medieval structure. Scholars knew that Toledo Cathedral once housed long-lost masterpieces of Renaissance music—reputedly stunning illuminated manuscripts of works by leading composers. But they surmised that looters had long ago whisked away the atlas-sized choir books.

Noone surmised differently. And, by 2003, he had turned up more than 170 parchment choir books, containing nearly 300 compositions by dozens of Renaissance masters, together with nearly 900 plainsong chants, primarily of Spanish origin. Most of the works were unknown until Noone found the manuscripts scattered within the cathedral.

The image above is from a manuscript of Franco-Flemish origin, presenting 30 polyphonic, or multiple-voice, pieces written for the French royal chapel in the 16th century. Although many of the manuscripts found by Noone had been virtually discarded and severely damaged (from sitting, for example, in standing water, in the cathedral basement), this one was preserved under lock and key, inside a chest in the sacristy—“a victim of overzealous caretaking,” Noone says.

Thanks to archival records kept by the cathedral, Noone was able to identify the composer. The page is the first in a Mass by Antoine de Févin (c. 1470–1512), beginning with the singing of the Kyrie (“Lord have mercy . . .”). The detail shows a portion of the bass part; the tenor, soprano, and alto parts occupy the remaining three quadrants of the spread. Records indicate that the cathedral purchased the 50-pound choir book some time before 1536 from an unidentified German. It was likely prized as an artifact, Noone says, “too expensive to be put in the hands of grubby musicians.”

The identity of the master illuminator who rendered the page’s precise miniatures on gold leaf remains a mystery. As Noone relates, the figures depict noblemen in Flemish garb. One gestures toward a banderole proclaiming the words sung at the beginning of Pentecost Mass: Spiritus Domini replevit orbem terrarum (“The spirit of the Lord filled the globe of the earth”). The scribe who set down the musical notation, probably in a separate workshop, is also unknown.

Before Noone’s discoveries—for which he received a cultural-preservation award from Spain’s King Juan Carlos in 2006—it was widely assumed that combatants in the Spanish Civil War (1936–39) or anticlerical forces decades earlier had plundered the collection. Noone, however, long argued that the cathedral’s prodigious archives would have indicated such a fate. After two decades of his visits, cathedral authorities invited him to search.

The Australian-born Noone came to Boston College shortly after making his discoveries. He has since turned out a dozen recordings of the music he recovered, working primarily with the London-based Ensemble Plus Ultra, which he directs. He is now supervising a project to catalogue and digitize all 22,000-plus folios unearthed.

Read more by William Bole