Auction houses cannot resist the temptation to hike estimates far too high in the hope of wooing consignors. This can kill a market, even when it is awash with cash the stupendous upheaval that shook the market for the "arts of the Islamic world" at the early October auctions in London is bound to have repercussions far beyond this particular category.

Never had the highly efficient Sothebys conducted a widely publicized sale of a noted private collection in which more than two - thirds of the lots —31 out of 44 to be precise —remained unsold. Such was the case on October 4 in a special evening session intended to lend solemnity to the occasion. The day after, in two long sessions dealing with property from various owners, the number of failures exceeded half the lots. .

When Christies took over on October 6, 47 percent of the works of art remained unsold. Even Christies South Kensington, where sales at the lower end of the market are usually highly successful, registered a 48 percent failure rate on October 7. .

Outsiders might conclude that money was short and that an abrupt downturn had hit the market in the highly diverse areas lumped together under the Islamic banner. Nothing of the kind happened. Huge prices were paid here and there. .

At Sothebys on October 4, an Iranian silk shirt dating from the late 7th or 8th century and dubbed "Post - Sasanian" —the Sasanian Dynasty that ruled Iran fell in a.d. 651, paving the way for the spread of Islam —brought 713,250. Woven with stylized confronted birds, the shirt suffered from browning that altered the color scheme. But the garment is unique in that style, and very few complete examples survive from that period. .

Moments later, another unique piece, this time ascribed to 10th - century Iran, fetched the second - highest price paid that evening. The green glass bowl decorated with a hare in low relief on each of its five lobes compares only with one other vessel, in the Treasury of San Marco in Venice. Previously unpublished, the Sothebys piece, which is an important discovery, shot up to a staggering 623,650 even though it was patched together from fragments. .

On October 5, a second silk garment from the Iranian world brought 481,250. It was ascribed to 8th - century "Sogdiana" —the Latin form of the Old Persian "Suguda" —the homeland of a northeast Iranian people in the area stretching from Samarkand to Bokhara, which later became a major center of Persian literature. .

Christies, too, scored with unique textiles. A pure gem labeled in the catalogue as hailing from "Central Asia" —although its stylized blossoms, leaves, and trilobate escutcheons are found across Iran in the 14th century —rose to ?301,500, matching the low estimate. It is in superb condition like most textiles known to have been preserved in Tibetan temples until the Chinese Cultural Revolution. .

Later, the ?zz9,z50 paid by the lone bidder for a 13th - century silver - inlaid casket from Mosul reflected the near - impossibility of obtaining Arab metalwork with intact inlay. However, the price did not even reach the low estimate, highlighting the real problem that bedeviled the October Islamic art sales: extravagant overestimation. .

The first casualty of an inordinate estimate was the private American collection that was the main focus of the October 4 session at Sothebys. Extensively publicized, it had received the unique honor of a seven - month - long exhibition in Z007 at the Art Institute of Chicago under the title "Perpetual Glory: Medieval Islamic Ceramics from the Harvey B. Plotnick Collection." But when estimates are 10 or zo times what might be reasonably expected for works that are neither extraordinarily rare nor in exceptionally good condition, the chances of success are slim. .

A large bowl painted with beautiful calligraphy in sepia brown on the ivory - colored slip was typical of the 9th - century pottery dug up at Neyshabur, the east Iranian metropolis. Unfortunately, a small bit is missing on the rim, cutting across the beginning of the inscription. Moreover, the decaying glaze allowed specks of earth to become ingrained into the surface, giving it a soiled appearance. The estimate stood at 200,000 to 300,000, plus a buyers premium in excess of zo percent. Knocking off a zero would still not make the piece cheap. It failed to sell. .

Similar misfortune hit most of the Iranian vessels that made up the core of the Plotnick collection, even if their provenance was conveniently obscured by the suggestion of a possible alternative —like "Iran or Central Asia" —or by conventional labeling with no foundation for ascribing, for example, to Iraq the wares with grayish - blue inscriptions or patterns on ivory ground that have come out of Neyshabur and other Iranian sites in large numbers. .

Had failures to sell stopped here, these could be blamed on their Iranian provenance, which would be known to the dealers who handle them. Such provenance bars reentry into the United States. But similar disappointment also befell fine pieces of Arab make. .

An imposing revetment tile that once adorned some major monument showed the shimmery iridescence that decaying glazes leave on pottery dug up in the Syrian town of Raqqa. The script, molded in low relief under the turquoise glaze, retains sections of a name, probably to be read "bn Abi " rather than "bin ibra" as suggested in the catalogue. The script is magnificent, but to understand calligraphy, you must read the writing, and to art lovers with a sense of history, the sight of a fragment made meaningless by being cut off from its context is deeply frustrating. Add that the tile was patched up from broken bits. The ?20o,ooo - to -?30o,ooo estimate was simply not plausible. Not surprisingly, no one budged.

Miscalculation likewise doomed the ultimate rarity, enhanced by a celebrated provenance. The base of an enameled glass candlestick ascribed to 13th - century Mamluk Egypt once belonged to George Eumorfopoulos, one of the greatest 20th - century collectors of Middle Eastern and Far Eastern objects. In 1910 the candlestick base was included in the epoch - making exhibition "Masterpieces of Muhammadan Art" in Munich. Sadly, when assigning to the glass piece a ?50o,ooo - to -?70o,ooo estimate, the experts overlooked the fact that the base of a candlestick that lacks its shoulder and nozzle is just a fragment. This too crashed unsold. .

Wild estimates were not confined to the Plotnick collection. The greatest objects in the October 4 sale were arguably three gilt - silver vessels probably executed in the century that followed the fall of the Sasanian dynasty. Consigned from a private European collection, they were done in by their estimates. A similar fate awaited an early 13th - century silver - inlaid ewer from the east Iranian province of Khorasan. No mention of provenance or previous publication is made in the catalogue, which suggests that it was recently exported from Iran or Afghanistan. The ?2 million - to -?3 million estimate was utterly unrealistic.

Was the ewer perhaps consigned to Sothebys at a moment when the Islamic department deemed it imperative to supplement the Plotnick works of art with spectacular pieces, no matter how excessive the estimate requested by the would - be vendor? As Sothebys experts thorough grasp of the art market is not in question, they are not likely to have been surprised by such failures. .

The unrealistic estimates reflect an intractable reality. Supplies of early art from the leading cultures in the Islamic world are thin —much thinner than in most other areas —and Christies and Sothebys are at each others throats to secure the bigger share of what remains available. One way of securing consignments is to accept, or even to offer, huge estimates. Consignors who are dealers or investors, as is very often the case, love this: selling even one out of three wildly estimated lots to billionaires naive enough to consult auction houses on how far they should go leaves sellers with a huge profit. .

So scarce are supplies these days, that auction houses now bring into their "Islamic" sales works of art from Western Europe under the thinnest of excuses. There was a touch of unintended irony about the catalogue for the October 5 session at Sothebys. The image on the cover shows a vessel in the shape of a bird, which is described as "a Romanesque gilt bronze aquamanile, Germany, early T2th century." The bird in question displays curious details, like the formal blossoms carried by the two scrolls engraved on the breast on either side of a long stalk, and a funny palmette crest rising from the birds head. Neither of these have parallels in Medieval art. This made one wonder whether the bird might be a much more recent artefact. Regardless of its period, the fact remains that the bird is not remotely Islamic. .

Neither is the object illustrated on the back of the Sothebys catalogue. Strictly nothing about the "fine and rare gilt - silver plaque, possibly a facing for a saddle, Central Asia, I3th/i4th Century or earlier" points to the Islamic world. The rendition of the oval lotus chalice, on which a fanciful bird stands, betrays some awareness of Chinese art, while the rhythmical scroll framing the bird calls to mind Tibetan art of later periods. The gilt bird of uncertain parentage remained unsold, as did the aquamanile of ill - determined age. .

Amusingly, the Sothebys experts even threw in "a rare Spanish cast gilt bronze Menorah, Spain, circa 13th Century." Some Islamic work of art! Actually, the "menorah" does not much look like the Jewish ritual utensil either: there are no devices to hold the candles. The object clearly requires further research to determine its provenance, more likely to be Indian than Spanish. At least, it is attractive and intriguing. It exceeded the high estimate at 39,650. .

Sothebys likewise got lucky with a blue and white porcelain ewer from China attributed to the Yongle period. A gilt copper cap and mount to the tip of the spout prove that the ewer found its way to the Ottoman empire, where Chinese blue - and - white was avidly collected, as it was in Iran. Considering the fuzziness of its motifs and the dull hue, the ewer did brilliantly at 181,250. .

Christies also selected some Western European works to beef up its offerings, although perhaps not with the utmost tact. Did the experts really expect a Crusader sword of the 14th century to inspire Muslim bidders with enthusiasm? A very crudely engraved Arabic inscription, which seems to indicate that the sword was picked up in the battlefield by Muslims fighting back Western invaders, did nothing to make the piece more attractive. .

Muslim artistic presence in Europe did not stir them either. Squeezed in between the sword and the dish were two silver inlaid trays of the late 15th century. Of the kind called "Veneto - Saracenic" until World War II, the trays are decorated with patterns borrowed from the Middle East, but like all Veneto - Saracenic wares, they reproduce shapes that have no parallels east of the Bosporus. Indeed, whenever such vessels have a provenance that goes back two or three centuries, it is nearly always Italy. On the other hand, both the technique and the occasional presence of their designers signatures, which give Muslim names in Arabic, leave no doubt that they were made by Muslims, somewhere in Italy. The presence there of Muslims from the Near East since at least the 13th century is demonstrated by tombstones carved with Koranic quotes and Arabic epitaphs as far afield as Genoa. .

The Sothebys trays were respectively signed "Mahrnud" and "Mahmud al - Kurdi." Saddled with ambitious estimates, they did not tempt bidders. .

More than once, objects that managed to sell did so on just one bid against the reserve. Such was the case with an Iranian bowl painted around the 12th century and featuring an angry goose, which was extravagantly overvalued and sold under the low estimate for 43,250. .

Grossly overestimated works were rescued only when they were of exceptional rarity. An Iznik lavender - ground bowl of the mid - T6th century, patched together from broken bits and missing two smaller fragments, almost tripled its estimate at $103,250. .

Perhaps the most serious evidence that bidders are no longer willing to comply with estimates set at arbitrarily high levels in order to suit the wishes of speculation - driven consignors came at Christies South Kensington, which brought up the rear of the Islamic sales. Excavated metalwork and pottery from the early periods fared poorly. Works on paper did better. Rightly or wrongly, these are perceived as less risky, because fakes are by and large more obvious. Works on paper are also less contentious because they cannot be suspected of coming out of looted sites, as is the case with virtually all objects recovered from underground caches. .

The October Islamic art discomfiture holds a lesson for the entire art market. The dwindling of available art affects every category, but abruptly pushing up estimates is not the answer for auction houses hoping to attract consignments. There is an invisible ceiling that will always stop prices from rising indefinitely —even if no one can say with certainty at what level that ceiling exists. .

In some areas, the end of the auction market may already be in sight over the middle term, say in 15 to 20 years. There simply wont be enough presentable works to build up public auctions. This is already the case with true Impressionist art, now sold together with "modern art" of the 20th century —which is in turn becoming increasingly rare at the top level. .

Contradictory movements will be observed during the winding - down phase of each category. Concerning "Islamic" art, truly unique works, particularly those set into the concrete of History with a capital H, will probably continue to ascend to extravagant heights because institutions and billionaires will furiously compete over last - chance opportunities. .

If a royal illustrated manuscript from Iran, Moghul India, or Ottoman Turkey, or some major piece of metalwork inscribed with the name of a sultan of great historical significance, should turn up, it might well attain a previously unheard - of level. Those that can be proved by documented evidence to have been in European hands in the 19th century or earlier, and thus to be woven into the fabric of Western culture, will soar sky - high, as Roman antiquities already do. .

But even works that are just fine will sell with increasing difficulty, because the number of collectors will decrease until they eventually vanish altogether —as might shortly be the case in Europe. .