Authorities in the German city of Munich have reportedly chanced upon a vast trove of priceless art that vanished during the Nazi regime and is today valued at about $1 billion.

The BBC cites the German magazine Focus in reporting German tax authorities found the store of 1,500 artworks, including those by masters like Matisse, Picasso and Chagall, hidden in the home of Cornelius Gurlitt, the reclusive son of a Munich art dealer.

Gurlitt had been reportedly suspected of tax evasion, and authorities found the cache after obtaining — and then executing — a search warrant for his Munich home in early 2011.

“This is a sensational find,” a spokesman for German Customs reportedly said.  ”A true treasure trove. It is an incredible story.”

And although the art was seized almost two years ago, the Focus story apparently represents the first public account of the works’ discovery.

Decades ago, many of the works had reportedly been declared “degenerate,” or “un-German,” by the Nazis, subsequently confiscated, and then re-sold to German collectors at below-market prices. Others had been reported stolen or were apparently bought for a pittance from Jewish art collectors who were under duress or forced to hurriedly emigrate.

The BBC cites the U.S. Holocaust Memorial Museum in estimating the Nazis seized about 16,000 works of art in all during their tumultuous, terror-filled reign in the 1930s and 1940s.

Of those pieces of art recovered from Gurlitt’s mansion, filled with rotting food and other bric-a-brac, 200 are reportedly the subject of international warrants.

According to the Focus report, as cited by the BBC, the collection is now held in a secure warehouse in Munich, until authorities sort everything out.

A break in the case reportedly came in 2010 when German customs officials conducted a routine check of a train from Switzerland and found the elder Gurlitt’s sole-surviving son aboard with 9,000 Euros and several empty envelopes.

Further investigation reportedly revealed Gurlitt was not registered with any German authorities or government tax and social service organizations, either. 

“He was a man who didn’t exist,” one official reportedly said.

Meanwhile, Cornelius Gurlitt’s famous father, Hildebrandt Gurlitt, was well-known in international art circles for having reportedly been tasked with none other than Joseph Goebbels, the Nazi propaganda minister, with monetizing the seized artworks deemed “degenerate.”

But the elder Gurlitt apparently kept much of the art, and after the war, claimed the collection had been destroyed in the 1945 bombing of Dresden, where he had a home.