“The Guarayo live with this music in their souls,” said Leidy Campos, 32, who teaches music in the village. “People say they were born with a violin in their hands.”
Across a field from the classrooms, Ideberto Armoye, a carpentry instructor, stood in a workshop of half-built violas and violins made from local cedar and mahogany. They were the only woods that could withstand the tropical heat, he said.
To prove his point, he pulled out a violin that had come recently from a factory in China.
“Anything happens to this instrument, look at this big crack,” he said.
While many of the era’s songs had been passed down orally through families in Bolivia, the orchestrations and choral works were thought to be lost. For years it remained one of the mysteries of the time: While Baroque music had been the bridge between the Jesuits and Bolivians, no one knew exactly how it sounded.
“I had to make a deep mental effort to imagine what it might have been like,” said Ennio Morricone, who composed the soundtrack to “The Mission” in the years before the manuscripts were discovered, using a combination of European and indigenous influences.
In the 1990s, Father Nawrot went looking for what might have remained of the written music, a search that led him to the Moxos area further west. He asked village elders in the area about manuscripts of that time. But first, he said, they had questions for him.
“For three hours they questioned me about my faith, my religion,” Father Nawrot recalled. “It was a complete reversal of roles.”
Eventually the Moxos leaders revealed something that astounded him. Thousands of pages of manuscripts, including music from baroque operas to concertos for solo instruments, some of which had been copied as late as 2005, had survived.
The copyists had even signed some of the scores “maestro capilla,” a Baroque-era title used by composers like Johann Sebastian Bach.
“The manuscript was never lost, we just didn’t know about it,” the priest said.
Through much of the 1990s, Father Nawrot worked with Mr. Vaca, the archivist in Concepción, to reassemble another collection of scores that had been found in the 1970s, including the Zipoli manuscripts that had been eaten by termites.
That body of work, which includes both copies of known works as well as unknown pieces written in Bolivia, is now known in classical music circles as Mission Baroque.
The music has admirers well beyond the Bolivian lowlands. One is Ashley Solomon, a professor at the Royal College of Music in London who traveled to the city of Santa Cruz this April to conduct at a festival of baroque music held once each two years at the former Jesuit missions.
“They took this music and made it their own — it’s more upbeat, more positive,” Mr. Solomon said. “The music lifts the soul, rather than self-flagellates, which is what you see in a lot of Western Classical music of the same time.”