A landmark exhibition of Russian art, Treasures from the Hermitage: Russia's Crown Jewels was set to debut at the Houston Museum of Natural Science on May 20 — but on that day, the gallery was left empty. The delay is the result of a recent ban by the Russian government on loans to American institutions, which has also impacted an exhibition opening in October at the Museum of Fine Arts, Houston, Gifts of the Sultans: The Arts of Giving at the Islamic Courts.

The conflict derives from the ruling by a U.S. judge demanding Russia return a sizeable group of religious books and rabbinic manuscripts seized during the Bolshevik Revolution and after World War II. The request for the return of the documents is advocated by Chabad, an Orthodox Jewish community in Brooklyn that began in 18th-century Russia.

Following the U.S. ruling, Russia announced an embargo of loans of works of art to U.S. museums. At the height of the drama, 37 icons from Moscow's Andrei Rublev Museum were withdrawn from the Museum of Russian Icons in Clinton, Mass. Several other stateside museums, including the Getty Museum and National Gallery of Art are being punished in the art diplomacy debacle.

According to The Art Newspaper, Russia's culture minister, Alexander Avdeyev, told the Russian media that the block will persist until the U.S. provides a "100% guarantee" that works lent to American museums will be protected. In April, Chabad assured U.S. State and Justice Departments that it will not attempt to seize any art or cultural objects or "disrupt in any manner the non-profit exchange of art and cultural objects between the Russian and American people."

A foreign ministry official reacted, "Unfortunately, the U.S. judge made an unlawful decision, which cannot be enforced in Russia, as a matter of fact." In a play of tit for tat, New York's Metropolitan Museum of Art is retaliating for having lost the loan of Cézanne's "Card Players" by dissolving an agreement to loan works to an exhibition on Christian Dior at the State Pushkin Museum in Moscow.

The current stalemate contrasts with decades of generous exchange between the U.S. and Russia. HMNS and Russian curators had been in discussions about the Treasures of the Hermitage exhibition since 1991.

"Obviously we're very disappointed because our exhibition consisted only of Russian objects and we were the only venue," says HMNS' Latha Thomas. "But we're hopeful. We do have an agreement that this exhibition will take place when this thing is settled. We're just hoping it will resolve quickly. The Justice Department is now involved, too."

The Hermitage exhibition has been organized by HMNS director, Joel Bartsch, who is also the curator of the museum's mineral collection. Bartsch's litany of partnerships with Russian institutions have brought such significant shows as 2000's Kremlin Gold: 1000 Years of Russian Gems and Jewels,and Fabergé: Imperial Jeweler To The Tsars. The museum capitalized on the void presented by the Russian ban by expanding the current milestone exhibition, ДРЕВНЯ УКРАЇНА (Ancient Ukraine) - Golden Treasures and Lost Civilizations, to include additional sacred icons.

Gifts of the Sultans, slated to open Oct. 23 at the MFAH, will continue as scheduled, but if the Russian ban isn't lifted, several works will be missing. The exhibition was organized in conjunction with the Los Angeles County Museum of Art, which unveiled the show on Sunday with 200 other artworks from the museum's permanent collection and borrowed from non-Russian lenders. However, the exhibition's planned centerpiece, an 18th-century Turkish tent embroidered in silk and gold that had been gifted to Catherine the Great and now belongs to the Hermitage, is noticeably not in attendance.

The likelihood of the exhibition's piece de resistance arriving in Houston is slim, says Francesca Leoni, curator of Islamic art at the MFAH. "The only real spectacular loss is the tent," she tells CultureMap. "Other than that, the other banned objects just added nuances to what remains an extremely accomplished exhibition concept. Obviously, it's unfortunate, but we can redistribute the objects without the centerpiece. That a diplomatic crisis affects a show that deals with the benefits of exchange — it's a bit of a paradox."