While visiting Italy in the 1960s, antiquities dealer Helen Fioratti and her Italian journalist husband acquired a souvenir: a red-and-green inlaid marble mosaic, which the couple purchased from Italian aristocrats and later re-purposed as a coffee table. But when Italian police came knocking on their apartment door in New York City decades later, the two learned that their “table” was actually a fragment of one of the Roman Emperor Caligula's pleasure ships, according to NBC News.

A mosaic tile that once adorned a pleasure barge owned by the Roman emperor Caligula. Manhattan District Attorney's Office

Caligula—who came to power in 37 CE and was assassinated just four years later—was a sadistic leader whose cruelty was perhaps only matched by his excess. The empire wasted taxpayer money on lavish construction projects. He's said to have drank pearls dissolved in vinegar and provided his horse with a marble stall and ivory manger.

When he wasn't conducting shameless affairs with allies' wives or making politicians run for miles in front of his chariots, Caligula enjoyed pleasure cruises on Lake Nemi, a small crater lake located about 15 miles southeast of Rome. The emperor is said to have owned three lavish vessels, which he used to host raucous parties. The barges were made of wood and decorated with gold, marble, ivory, and, yes, mosaic floors. 

At least two of these cumbersome boats sank, and they were excavated between 1928 and 1932 under the Italian dictator Benito Mussolini, according to The Daily Beast. These artifacts were displayed in a museum, which was used as a bomb shelter during World War II. Many of their mosaic tiles were destroyed—but against all odds, a floor fragment from the ships ultimately ended up across the world in Fioratti's living room.

It's unclear how, exactly, the Italian military police's Art Recovery Unit and New York's district attorney office learned of Fioratti's mosaic. (She thinks they may have spotted it in a magazine photo shoot of her apartment.) Authorities seized the artifact and returned it to Italy in a repatriation ceremony on October 19, along with a host of other recovered stolen Italian artifacts.

Fioratti—who claims that she legally purchased the mosaic for thousands of dollars—won't face any criminal charges, although she told NBC she's sad to see the relic go.

[h/t NBC News]