By Ed Stoddard

FORT WORTH (Reuters Life!) - A rare exhibit of Christian art in its infancy, including the earliest known depiction of Jesus' crucifixion, is an evocative display that holds as much historic, as religious, appeal.

"Picturing the Bible: The Earliest Christian Art", at the Kimbell Art Museum in Fort Worth, Texas, includes gems, frescoes, marble sculpture and lavishly decorated crosses dating from the third to the six centuries.

It is a dazzling collection of artefacts showing how the first Christians venerated a faith that went from being an object of persecution to the state religion of the Roman Empire.

"There only has ever been one other major exhibition anywhere which addressed this period of Christian art and that was at the Metropolitan Museum of Art in New York 30 years ago," said Timothy Potts, Kimbell's former director and exhibit organiser.

"This is because the material is so rare and fragmentary and fragile and for many institutions, it is some of their most valued artefacts," he told Reuters.

Many Texans like to think they reside in the heart of the U.S. "Bible Belt", the southern heartland of conservative Christianity, and the exhibit offers them the chance to see the artistic roots of their faith first hand.

The exhibit was made possible by loans from the Vatican, the Bargello and the Laurentian Library in Florence, the British Museum and the Louvre among others. Many artefacts have never or rarely been lent out before.

Among the highlights is an ornate gem-encrusted cross -- on loan from the Vatican Museums -- that was presented by the Emperor Justin II to Pope John III in the late sixth century. Wood embedded in it is said to come from the "True Cross" that Christ was crucified on.

"These pieces of art have interest beyond their historical and artistic value, they have deep meaning to people on a religious level," said Potts.

One of the more intriguing pieces is also one of the smallest: a minute bloodstone that is frayed at the edges but still portrays a fully intact image of the crucifixion.

Dating from the late second or early third century, it is believed to be the earliest known artistic rendering of Jesus on the cross.

Although a central tenant of the faith, early images of the crucifixion -- at least surviving ones -- are very rare.

"Why early Christian artists shied away from it is unclear," Potts said. Explanations include the possibility that a saviour who could be humiliated in such a way would compare unfavourably with all-powerful pagan gods who were still, or had been recently, in vogue.

The exhibition runs until March 30, 2008. For details check http://www.kimbellart.org/