The legend has persisted for centuries that the Vatican is hiding the solid gold menorah -- if not at St. John Lateran, then in a cave at the Vatican. Jewish religious and political leaders continue to ask the popes to return the piece.

Arnold Nesselrath, director of the Department of Byzantine, Medieval and Modern Art at the Vatican Museums, said the mosaic from the time of the reign of Pope Nicholas IV is the last the Vatican heard of the famous menorah. Excavations under the altar of St. John Lateran and the surrounding area in the early 20th century turned up no trace of the treasures.

Still, he said, the legend documents just how important the menorah is in Jewish culture.

Francesco Leone, the art historian who prepared the exhibit catalogue, told Catholic News Service the most historically reliable explanation of the Temple menorah's fate is that it was taken as booty from Rome by the Vandals or Goths before the end of the fifth century and melted down.

The oldest object in the exhibit is the "Magdala stone," a carved block from a synagogue in the Galilee excavated in 2009. The stone, which has a carved menorah on one side, is from before the time of Jesus.

Alessandra Di Castro, director of the Jewish Museum, said working with the Vatican Museums and with scholars both of them called on to help with the research, "we experienced firsthand how working together brought each of us new understanding."

Nesselrath agreed, saying, "The collaboration was a process of deepening respect for what is sacred to the other."

Rabbi Riccardo Di Segni, the chief rabbi of Rome, writing in the exhibit catalogue said, "The Jewish link with the menorah is ancient, strong and full of symbolic significance, and the link has never been broken."