The Expulsion From the Garden of Eden was returned to Mexico by the San Diego Museum of Art, but most art stolen from Mexican churches is never found. ((Sandy Huffaker/Associated Press))

The Mexican government has launched a vast cultural undertaking: to get all the country's churches to catalogue, register and photographtheir sacred art.

Mexico has a wealth of colonial art, including paintings, sculptures, stained glass and sacred objects, spread among its churches.

But a demand for such works among collectors has made the contents of rural parishes a tempting target for thieves.

The National Institute of Anthropology and History estimates 1,000 colonial pieces have been stolen since 1999.

The demand for such art has been growing for the last 10 years.

But it's difficult to get a handle on the size of the problem, because no one knows exactly what's out there.

The Mexican government is urging priests and local congregations throughout Mexico to create a record of what they have.

It has asked them to photograph, measure and describe objects in an attempt to create a catalogue of objects.

"Cultural patrimony is a nonrenewable resource," Clara Bargelli, an art historian at the National Autonomous University in Mexico,told the New York Times.

"We are suffering losses, partly because we still do not have an accurate account of what exists and where."

Last month the San Diego Museum of Art returned an 18th-century painting of the Expulsionfrom the Garden of Eden to Mexico, after discovering it was stolen.

The piece had been taken from a rural church and smuggled out of Mexico, despite laws that ban legal exports of colonial art.

Database of stolen art

The government-run National Institute wants to create an internet database of stolen art, so that dealers and collectors can check the provenance of items that pass through their hands.

But many rural parishes don't have computers or the internet, let alone access to digital cameras.

And members of the clergy are worried the project may lead to the government seizing sacred objects to protect them in a museum.

Most Mexican churches don't even lock their doors and there is little awareness of the value of what seem like everyday objects, however beautiful.

"Virtually every village in Mexico has works of art. They are just magnificent," said Marion Oettinger of the San Antonio Museum of Art.

She welcomed the news of the catalogue, saying it was time Mexico sent experts into remote areas to make sure everything is counted.