47. Is There an Ultimate Authority in Authenticity? Testing and Retesting Alexander the Great

On display in the Harvard Art Museums is a statuette of Alexander the Great, sometimes referred to as the Alexander Nelidow after its first known owner.¹ The statuette first appeared in the Istanbul bazaar sometime before 1897.² The original condition of the surface when excavated can only be guessed at: the surface had already been cleaned of any unsightly burial accretions by the time the first images appear.³ Alexander is depicted as a nude youth, standing with his left arm raised, probably to grasp a spear. His head is turned sharply toward the left, while his right arm is bent with his hand placed on his right hip (fig. 47.1a–b). His torso is heavily muscled on the front and back. The legs below the knee are restorations. The statuette was sold at auction in 1911.⁴ By 1954, it was in the possession of C. Ruxton Love Jr.,⁵ who donated it to Harvard’s Fogg Art Museum in 1956.⁶

The Alexander statuette’s authenticity as an ancient work has been called into question on occasion, most recently in 2014 when the results of lead-isotope analysis indicated that the statuette had an isotopic composition distinct from that of ore sources believed to have been used in Graeco-Roman times and from that of published copper alloy and lead objects of the period.⁷ These analytical results provided the impetus to reevaluate the Alexander and to wonder if there is a final authority in authenticity studies. Is there ever going to be a point where one can look at objects and say, definitively, this one is fake and this one is an authentic antiquity?

Some light can be shed on this question using the work that curators, conservators, and material scientists have been doing for almost fifty years on bronzes at the Harvard Art Museums, particularly on the almost 1,300 copper alloy objects in the museums’ Ancient Art Department in preparation for the online special collection Ancient Mediterranean and Near Eastern Bronzes at the Harvard Art Museums.⁸ All objects were examined by members of the Straus Center for Conservation and Technical Studies for information on manufacture and condition, almost 1,000 were written up by art historians, and about 900 were tested for alloy composition using a variety of destructive and non-destructive methods. These techniques included ICP-MS/AAA, XRF, EMPA, SEM-EDX, and ICP-OES.⁹ For this paper, we shall also draw on the data of a group of modern copper-alloy objects and pieces of uncertain antiquity for comparison with data from the Alexander, in order to explore issues that might help determine the statuette’s authenticity.

Previous doubts about the Alexander Nelidow have come from the art historical perspective. The statuette has been published about thirty times between 1897 and the present.¹⁰ In his 1898 monograph on the statuette, Oskar Wulff suggested that it is a copy of a statue known to us as “Alexander with a Lance” by Lysippos (a work that was possibly described by Plutarch¹¹). The identification is based on the arrangement of his hair, the stance­—holding a spear now lost—and the left turn of his head, which would fit the possible descriptions of the statue.¹² Although most publications of Harvard’s statuette accept that it does represent Alexander the Great (or a Hellenistic ruler), that it may be a copy after a Lysippan original, and that it was made in the Hellenistic or Roman periods, questions remain as to whether it is a copy based on “Alexander with a Lance,” and indeed if such a statue even existed. A few of these publications reascribed the Alexander Nelidow from an ancient date to a more recent, even modern, one. The most important of these was by Diana Buitron, who suggested that the Alexander is a Renaissance piece based on stylistic similarities, particularly in the musculature, that she saw with certain fifteenth- to sixteenth-century AD bronze statuettes.¹³ Stylistic criteria can be highly subjective, however, and Buitron’s arguments are not concrete enough to securely date the Harvard statuette.

Copies

When looking at comparative pieces for more objective criteria by which to identify fakes, one fact that has emerged is that some of the statuettes in Harvard’s ancient art collection are modern or likely modern copies (exact or only slightly adapted) of other statuettes. Of course, close copies of large-scale bronze sculptures are known,¹⁴ but the statuettes in question are not copies of standard statue types. It is worth stressing that the antiquity of these statuettes was not called into question based solely on their status as duplicates, but was based on a combination of criteria, including lack of corrosion or alloy composition that is inconsistent with securely dated ancient pieces.

There are statuette types that are known “souvenir” replicas, like Harvard’s copy of the Dancing Faun from Pompeii, which was probably made as a souvenir of the Grand Tour.¹⁵ Its corrosion pattern does not suggest long-term burial, and its alloy composition is inconsistent with that of ancient pieces. Another example of this type may be a plaque of a sacrificial ram with attendant, which entered Harvard’s collection as an antiquity.¹⁶ This piece lacks corrosion and contains over 5% zinc, both of which are red flags for fakes;¹⁷ it was nevertheless accepted as likely ancient until a very similar version from Pompeii was identified in the Museo Archeologico Nazionale, Naples. The similarity of the pieces suggests that the Harvard version was copied from the Naples bronze. As a result, the Harvard example was reclassified as modern.¹⁸

Another questionable object, of a Sardinian shepherd and ram group,¹⁹ is probably a forgery meant to appear ancient. Its constituent alloy is completely unlike other Sardinian pieces, containing around 15% zinc: of about 130 such objects with published alloys, only one other has more than 1% zinc.²⁰ The corrosion is thick, up to 1.5 mm in some areas, but jumbled and uneven, sometimes lacking the usual layer of red cuprite under the green corrosion. It was found to have great similarities to a wrestler group in the Museo Archeologico Nazionale di Cagliari: the Harvard statuette mimics one of the wrestlers and replaces the other figure with a ram.²¹ A draped female figure in the Harvard collection, which also lacks indications of corrosion from long-term burial and has an alloy containing over 30% zinc, is identical to at least 4 and up to 11 other statuettes.²² It is also uncertain which statuette in this case would be the original upon which the others are based.

While the authenticity of a statuette is not immediately confirmed or undermined by being a close copy (or not) of another piece, this is often a cause for concern, particularly when combined, as in the above cases, with other reasons to doubt the objects’ antiquity. In contrast, although it has close cousins, both large and small scale,²³ the Alexander Nelidow is not an exact copy of any other known statuette, so we must turn to other evidence to support, or refute, its antiquity.

Manufacture

In the process of examining objects for the ancient bronzes special collection, the conservation team identified some oddities related to methods of manufacture that have implications for the authenticity of some objects. One piece that has been difficult to authenticate portrays a comic actor in the role of a kitchen slave (inv. 2001.257).²⁴ The raised ridges along the exterior of the legs appear to be traces of piece-mold lines, a feature one would not expect to find on a Graeco-Roman bronze and which may be an indication that it was cast from a mold taken from an existing copper-alloy statuette. Filed-down mold lines were also observed on the statuette of the draped female figure mentioned above (inv. 1932.56.27).

The conservation team was recently able to compare Harvard’s statuette of the orator Demosthenes (inv. 2007.221), based on a famous statue of the third century BC by Polyeuktos,²⁵ with an aftercast of the statuette made in Germany in the early twentieth century.²⁶ Comparison of X-radiographs of the ancient Demosthenes statuette and the aftercast reveals very different interiors, with a clear armature on the inside of the aftercast (figs. 47.2a–b, 47.3a–b). Study of the object at the Straus Center for Conservation and Technical Research revealed that the thick corrosion on the surface of the original is replicated on the aftercast as a rough, bumpy surface with no indication of corrosion products; a similar surface also appears on the draped female statuette described above (inv. 1932.56.27).

In terms of manufacture, there is nothing unusual about Alexander: the statuette is solid cast, probably by a lost-wax technique, although due to the surface condition it cannot be determined with certainty whether it was a direct or indirect cast. Again, the Alexander shows none of the concerns that were noted for other suspect pieces and were used to help condemn these as modern.

Corrosion

The presence of corrosion cannot be used by itself to authenticate or date an object, but its total absence is a very good indication, in combination with other data, that a piece may not be ancient. The mineralized surface of the Alexander statuette was pared down to the interface of preserved metal before its earliest photograph was published in 1898.²⁷ In spite of this extensive “restoration” treatment, Alexander retains thick patches of red and green corrosion products usually associated with cuprite and malachite, although we have tended not to use analysis to confirm the identification of corrosion products (fig. 47.4a–b). Thick corrosion layers and intergranular corrosion can both be good indicators of long-term burial—and thus great age—but it is impossible to extrapolate from these the exact length of time an object was buried. That said, one must bear in mind that corrosion or patination can be created or enhanced artificially.²⁸ The cuprite on another Harvard bronze—a modern copy of half of a fifth-century BC Etruscan candelabrum group portraying a standing warrior—also has some red and green corrosion; in this case, the red corrosion was confirmed by Raman spectroscopy to be cuprite (fig. 47.5a–b).²⁹ As with the Sardinian shepherd-and ram-group, the thickness of the corrosion varies. The corrosion on the standing-warrior bronze could be mistaken for evidence of long-term burial if we did not know that the piece was a copy of an original candelabrum group excavated at Marzabotto, Italy, currently in a private collection, which the owners had reproduced for the Marzabotto Museum.³⁰ Harvard’s warrior could easily have been made at the same time as the other known copies. Harvard also owns a copy of another candelabrum finial from Marzabotto of a youth carrying an amphora, which was also replicated and sold.³¹ Results of compositional and isotopic analysis indicate that the metal composition of the two replicas of Marzabotto bronzes at Harvard is very similar, perhaps from the same batch of metal, though not the same pour.

Metal Alloy

The usefulness of alloy analysis to date bronzes has been debated due, among other things, to the recycling of metal throughout history.³² Nevertheless, alloy analysis has revealed broader patterns and helped to identify anachronisms. Certain alloys seem not to have been used during specific periods: brass, an alloy of copper and zinc, for instance, has long been thought to be uncommon in antiquity before the Roman times. Yet, even there, as we use different tools to gather more data on the composition of copper alloy objects, the overall picture becomes more complex. Brass, we now know, does occur before the Roman period—but is still rare and occurs only in certain contexts or in certain types of objects.³³

In the 1970s, Harvard’s Alexander was sampled and tested by X-ray fluorescence spectroscopy (XRF), which suggested that it contained 1% zinc. More recent tests give quite different results, with only a trace or no zinc detected.³⁴ The variation between the datasets probably reflects improvements in analytical methods since the 1970s and the benefits of sampling for clean metal versus surface analysis, as the readings of surface composition are often distorted by the presence of corrosion. As a leaded bronze with trace zinc, Alexander’s alloy composition is entirely normal for a Roman statuette. Based on data gathered at Harvard and further afield, it can be noted that the presence of (1) zinc above a few percent, (2) cadmium above the detection limit, and (3) high zinc without tin are all suspicious for ancient copper-alloy statuettes.³⁵ Of the 600 Harvard objects tested, around 80 objects had 5% zinc or higher (with a maximum of 48% zinc): 80% of these high-zinc pieces are known or suspected to be fakes or are known to date from the Byzantine to Islamic periods, and almost all of the statuettes with zinc above 5% are believed to be fake based on analyses of their corrosion products and art historical comparanda.³⁶

Lead-Isotope Analysis

Lead isotope analysis relies on the fact that ore sources containing lead have a characteristic isotopic “fingerprint,” which can help to pinpoint the source of a lead-containing copper alloy or lead deposit. However, interpretation of the isotopic composition of an object is complicated because more than one lead-containing source may be present, either due to mixing of metal ores in the original alloy or (more commonly) as a result of mixing from the recycling of metal objects. Lead isotope analysis of Harvard’s Alexander and Demosthenes statuettes was performed in 2014. Both of these statuettes contain over 5% lead, so the measured isotopic composition of both reflects the ores of the lead that was deliberately added as an alloying ingredient, rather than being inherited from trace lead within the copper ores. A comparison of the lead isotopes of the two statuettes to known Graeco-Roman lead ore sources shows that the Demosthenes and the ores plot along the same line, while Alexander’s lead is notably separate (fig. 47.6).³⁷ In order to better understand the lead isotopes of modern or fake copper-alloy objects, we sampled several known and suspected later copper-alloy objects at Harvard, as well as a few authentic pieces for comparison (fig. 47.7).³⁸ While the modern pieces and replicas cluster to higher values, they still plot along the line of possible Graeco-Roman lead ores. Even when we enlarged the plot to include more exotic ores from outside Europe and the Mediterranean, such as those from India³⁹ and Australia,⁴⁰ and modern gasoline lead,⁴¹ from lead added to gasoline, which gives a good average for available modern lead (fig. 47.8),⁴² the isotopic composition of lead from the Alexander Nelidow remained separate. This separation cannot be explained by the melting down and reuse of metals with different lead sources: recycling would simply give values that plot along the same line. The only way to produce such an anomalous value is to find an exotic source plotting above the line. One such possibility is provided by lead ores from Morocco, which do fall in a distinct field above the main isotopic line close to the value of the Alexander statuette (fig. 47.9).⁴³ Although more research is needed to determine whether Moroccan ores were actually exploited in the Roman period, studies of lead curse tablets from Roman Carthage show that Tunisian lead was used in these objects, proving exploitation of at least some lead sources local to North Africa in the appropriate period.⁴⁴

In the end, this unusual lead-isotope analysis result is not enough to condemn the statuette, as it had seemed at first, but neither should one use this result to make statements about its date, origin, or authenticity. There is still a surprising lack of available lead-isotope analysis of Roman copper-alloy objects. In order to better interpret the isotopic composition of suspect pieces, a reliable database of well-provenanced Roman bronzes (ideally statuettes and similar objects) on the one hand, and of modern and late bronzes of similar typology on the other, is required to characterize more clearly how the data may vary. This would seem to be an ideal research project for the future.

Conclusions

This paper has given a very brief overview of a large trove of data in order to explore issues of authenticity in relation to copper-alloy objects generally, and to revisit earlier doubts concerning the antiquity of the Alexander Nelidow in particular. Research into the style, method of manufacture, surface corrosion, alloy, and lead isotopes produces no definitive evidence that this statuette is other than ancient. While a copper-alloy artifact can never be completely vindicated once questions have been raised about its authenticity, the systematic collaboration between curators, conservators, and material scientists can significantly elucidate and clarify our understanding of the piece. But it is important that these professionals work closely together, understanding each other’s methodologies, aims, and conclusions.⁴⁵ More careful examination of objects under microscopes, more sampling, and more research and analysis by such interdisciplinary teams can vastly improve knowledge of our collections.

Notes