The Porsche Cayenne is now 20 years old, having originally debuted at the 2002 Paris International Motor Show. But Porsche's first SUV could have taken a very different development path from the version that ultimately ended up on stage in the French capital.

The first-generation Cayenne was almost based on the Mercedes-Benz M-Class (the predecessor to today's GLE-Class), Porsche has revealed.

Mercedes-Benz ML 320

Mercedes-Benz ML 320

When Porsche began mulling a third model alongside the 911 and Boxster, it considered five concepts that eventually got whittled down to either a minivan or an SUV. The minivan idea was nixed by the automaker's American branch, which viewed an SUV as more appealing to the higher income buyers Porsche wanted to attract.

Porsche still had fairly limited resources for vehicle development at the time and sought a partner for the SUV project. Around the same time, Mercedes was preparing to launch the M-Class. The two automakers had recently collaborated on the Mercedes 500 E sports sedan, and Mercedes wasn't opposed to a second partnership.

Porsche Cayenne prototype in Weissach, Germany, in 2000

Porsche Cayenne prototype in Weissach, Germany, in 2000

"At that stage, we envisioned the Porsche SUV as a high-performance offshoot of the Mercedes," Klaus-Gerhard Wolpert, former head of the Cayenne product line, said in a statement. It would have shared some technology with the M-Class, but with unique exterior styling and Porsche-supplied engines and chassis components, Wolpert said.

The two automakers began talks in 1996, but the deal fell apart over financial disagreements, according to Porsche. Mercedes launched the M-Class solo in 1997 and it became one of the automaker's bestsellers. In June of that year, Porsche decided to partner with Volkswagen to develop the Cayenne alongside the first-generation Touareg. Parts commonality, as well as use of a VW factory for production, made the arrangement financially viable for Porsche. The rest, as they say, is history.