What determines the price of an antiquity? Its quality, measured by its artistic or art historical importance, or its provenance? And if it is provenance, is it the prestige and reputation of a previous owner that adds most to price, or evidence that the antiquity has been in circulation long enough to have passed a legal or ethical threshold of acceptable ownership? Recent received wisdom is that antiquities with a provenance stretching back to before 1970 command a price premium, 1970 being the date of the UNESCO Convention on the Means of Prohibiting and Preventing the Illicit Import, Export and Transfer of Ownership of Cultural Property. The idea of a pre-1970 price premium has gained traction since 2008, when the Association of Art Museum Directors adopted 1970 as a provenance threshold for determining the acceptability of an acquisition. Going forward, collectors wanting to gift or bequest antiquities to museums would need to be careful about this 1970 threshold, and make their purchasing decisions accordingly. Over time, this accumulating customer preference for a pre-1970 provenance would promote a market in well-provenanced antiquities and suppress the market in recently stolen and illegally-traded ones, something I have called autoregulation. Or at least, that is how the argument goes. Reliable statistics making the case for provenance one way or another are hard to come by.
What do art market professionals themselves have to say on the subject? During the run-up to its 25 April 2017 New York Antiquities sale, Christie’s specialist Laetitia Delaloye offered her thoughts on what determines the price of an antiquity. First and foremost, she said, it is a matter of size – ‘As a rule, larger pieces in good condition will sell for the highest prices, while smaller pieces are more likely to survive and are therefore more common on the market’. Then, obviously perhaps, she also highlighted the importance of condition – the extent to which a piece has been repaired or restored. A signed piece is always good too. For provenance, she believes it is the name or reputation of previous owners that is likely to add ‘significant value’ to a piece, and she did not mention any legal or ethical advantages of a pre-1970 provenance, or any positive effect such a provenance might exert upon price.
Delaloye’s post was prefacing the sale on 25 April of a collection Greek figure-decorated pottery from a ‘Manhattan Private Collection’, which included 15 Attic black-figure vessels. Lot 202, a hydria, had an impeccable provenance that could be traced back to the collection of Reverend John Hamilton-Gray and Elizabeth Caroline Hamilton-Gray, which was sold at auction at Sotheby’s London in 1888. It passed next through the possession of the Pitt Rivers family before moving through Geneva to join the Manhattan collector. Lot 206, a trefoil oinochoe, also had a long provenance, first seen at Drouot in 1903 and featured in several publications since then. Alongside these two pieces with a published provenance that could be traced back to before 1910, lot 207 had been first published in 1962, six vessels had been first published later than 1970, and six had not been published at all.
This first chart plots the maximum dimension of each vessel sold (measured in centimetres) against its realised price (in USD). In graphic confirmation of Delaloye’s belief that ‘bigger is generally better’, there is a strong correlation between size and price. The three largest vessels achieved the three highest prices, and not one had a provenance that could be traced back to before 1970. Size is without doubt the primary determinant of price. On the other hand, there is a suggestion that within their size class the well-provenanced lots 202 and 206 performed better than their more poorly-provenanced fellows. Thus there is evidence here that when corrected for size, so that like is compared to like, a long provenance does indeed carry a price premium. By itself, however, this would not be enough to exert a decisive influence on the market. Auction houses would be keen to sell the highest-price vessels possible, and so would discriminate in favour of size, not provenance. The Manhattan collector acquired four vessels (lots 205, 207, 215 and 216) from Nicolas Koutoulakis in the 1980s. Koutoulakis has been described as the ‘dean of all antiquities dealers active in the Arab world and beyond’ . He figured centrally on the organigram seized by the Italian Carabinieri in 1995 and his name has been associated with the histories of several illegally-traded antiquities. The discussion of due diligence in article 4(4) of the 1995 Unidroit Convention on Stolen or Illegally Exported Cultural Objects recommends among other things that ‘regard shall be had to all the circumstances of the acquisition, including the character of the parties’. Thus any names of suspect dealers appearing in the provenance of an object should raise red flags, and discourage its purchase, though that does not seem to have happened here. The prices realised by the Koutoulakis vessels were in accordance with their size. They offer further evidence that a questionable provenance does not unduly discourage purchase nor does it have a serious negative impact on price.
 Krosney, Herbert, 2006. The Lost Gospel. Washington DC: National Geographic, at page 66.