The 1866 painting of a naked woman lying with her legs open, has only relatively recently shown in public.

Normally on display at Paris's Musee d'Orsay it has been lent to Vienna's Leopold Museum for the retrospective.

Hans-Peter Wipplinger, artistic director at the Leopold Museum, told AFP it was only the fourth time the work had been cleared for a loan abroad.

It was originally bought by Khalil Sherif Pasha, widely known as Khalil-Bey, an Ottoman statesman and diplomat posted in Paris and then Vienna. It later passed through the hands of several private collectors.

"Courbet deliberately created the painting for the private sphere; in the 19th century, a public presentation would have been unthinkable," says the exhibition notes.

It was only in 1955, that "The Origin of the World" was put on public display.

The painting is the centrepiece of the retrospective, along with another one sold to Khalil-Bey, "The Sleepers" an 1819 painting that shows two naked women sleeping togeether.

The Vienna show, with 128 different works, is one of the biggest retrospectives ever devoted to Courbet (1819-77), who defied the conventions of his day.

"We show for the first time Courbet's last four years, which he spent in Switzerland," said Wipplinger.

The retrospective, including several other works loaned from other countries, features paintings, sculptures and drawings.

The show also places Courbet's work in contrast with those of contemporary artist Yan Pei-Ming, who names Courbet as one of his great influences.

"Gustave Courbet: Realist and Rebel", opens on Thursday and runs until June 27.