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A Storm of Controversy on the Dating the Eruption of Thera

Ever since I became interested in the subject of Minoan culture, there has always been a problem of dating the volcanic eruption of Thera (see: The World Ended When Gods Turned against the Minoans) and related to it speculations about the reasons why the Minoan culture on Crete collapsed at all (see: Disaster of the Bronze Age Spreads Beyond the Epicenter).

For the periodization of the history of the Minoan world on Crete, the so-called palace system is usually used (“Kultura minojska” 2020). It is mainly based on archaeological stratographic research, which gives time frames for successive phases of the existence, growth and the fall of Minoan palaces on Crete (Ibid.). Following so the Minoan chronology given by archaeologists, the volcanic eruption occurred around 1500 BC. (Ibid.). It therefore ended the first phase of the Late Minoan period (LM IA) (1600-1500), when the Minoans were at their heyday, and started the second phase of the Late Minoan period (LMIB) (1500-1450) (Ibid.). Accordingly, the Minoan culture had survived the eruption and lasted until around 1100 BC., but it had never regained its former power, which eventually led to its collapse (Ibid.).

Nea Kameni: volcanic craters on Santorini Island (previously Thera), June 2001. Photo by Rolfsteinar – Own work (2001). CC BY 2.5. Photo and caption source: “Minoan eruption” (2020). In: Wikipedia. The Free Encyclopedia.

On the other hand, however, there is another chronology obtained from Thera’s geological research, which takes the eruption back over a century! According to geologists, Thera erupted around 1620 BC. (Mitchell 2011), which is when the archaeological chronology suggests the end of the Middle Minoan period (MM), namely, around 2000 – 1600 (1700) BC. (“Kultura minojska” 2020). According to archaeological finds, it was also a period of natural disasters but they were mainly associated with earthquakes on Crete. Were they related to the eruption of Thera? It is possible … Yet, if the volcano erupted in the seventeenth century BC., badly affecting the Minoans of Crete, how could their culture flourish then in the sixteenth century BC.? What is more, such dating results would also change historic witnesses of the eruption, especially in such empires as Egypt. Is there then any notice of the natural disaster in their records or elsewhere? Such written evidence present outside the Minoan world could greatly support or deny one of the given chronologies.

Finally, how is it possible at all that the reliable study results of the both interdisciplinary but related sciences could be so different and hence confusing?

A major controversy between archaeology and geology

Dating the Thera’s eruption has become one of the major controversies in academic world.

The Lillies fresco from Akrotiri, Santorini. Photo source: Antiquated Antiquarian (2015) “The Minoans: Frescoes”. In: The Stream of Time.

“For more than two centuries archaeologists have refined the Bronze Age Mediterranean historical framework by observing the relative order of superimposed levels on a series of sites (MacGillivray 2007:150). Next, they established inter-site relationships based on common cultural characteristics – primarily in ceramics, art and architecture” (Ibid:150). “Based on archaeological correlations between the Aegean, Egypt and the Levant, the eruption of Santorini was believed to have occurred around 1500 BC., after the beginning of the New Kingdom in Egypt, [that is to say in the sixteenth century BC., when the Queen Hatsheput mainly ruled (see: Last Queen in the Valley of the Kings)]” (Ehrlich, Regev, Boaretto 2018). “The traditional date around 1500 BC. was first proposed in  the 1930s by Marinatos. It has […] been, [however], challenged by a controversial new date of around 1600 BC., dividing prehistorians into two camps and generating heated debate” (Castleden 1998-2001:191).

Turning for help to ancient Egyptians

In 1980s, two scientists first disputed the archaeological dating (History Channel 1980s). These were the German geologists, H. Pichler and W. L. Friedrich who radiocarbon-dated the charcoal found in the volcanic rocks (Ibid.). According to the results they obtained, the eruption of the volcano took place around 1650 BC. (Ibid.). It would mean that Thera’s explosion was over one hundred years earlier than it was primarily thought (History Channel 1980s; Wengler 2009). Accordingly, “the Minoans in [their] mature stages [would have been] contemporaries of the ‘Foreign Princes’ of Egypt’s Hyksos period, a century earlier than Hatshepsut’s reign in the historical chronology” (MacGillivray 2007:150).

Statue of the famous Egyptian queen Hatshepsut who belonged to the Eighteenth Dynasty. Today on display at the Metropolitan Museum of Art, MET, New York. Created: circa 1479 BC. CC0. Photo source: “Hatshepsut” (2020). In : Wikipedia. The Free Encyclopedia.

In this case, some scholars turn for help to Egyptian texts, which “may give a clue to the absolute date [of Thera’s eruption” (MacGillivray 2007:159). And they find there interesting records, which may actually refer to the volcanic explosion and its devastating results. At the turning of the fifteenth century BC., “one of Hatshepsut’s best known dedications was the rock-cut temple to the lioness-goddess Pakhet, near Beni Hasan in Middle Egypt. […] Here, Hatshepsut carved a very revealing account of herself and her deeds in that region over the architrave” (Ibid.:159). Some scholars interpret the text “as Hatshepsut sending braziers to her subjects driven by raging storms and total darkness into the temples” (Ibid.:159). One of her deeds “was to care for refugees who swarmed into Middle Egypt from the Nile delta because of the incursion of the sea there” (Ibid.:160). There is also another text from much later Ptolemaic period (third or second centuries BC.), but referring to the events having happened during the Eighteenth Dynasty (Ibid.:160). Namely, the words of an Egyptian scribe recall biblical descriptions of darkness covering the earth (Ibid.:160). “[He writes:] ‘there was no exit from the palace by the space of nine days. Now these days were in violence and tempest: none, whether god or man, could see the face of his fellow’. This nine-day period reads suspiciously like an Egyptian multiple of three, which meant ‘a long time’, and so refers to a lengthy period of storms and darkness” (Ibid.:160).

The Tempest Stela of Ahmose. Reconstruction of the face (R) and back (L). (Malcolm H. Wiener and James P. Allen, 1998). Source: University of Chicago (2014). “Tempest Stela: World’s Oldest Weather Report Could Revise Bronze Age Chronology”. In: The Epoch Times.

Additionally, there is also a very interesting writing on the fragmented stele, ascribed by some scholars to Ahmose, the pharaoh and founder of the Eighteen Dynasty in the middle of the sixteenth century (Jacobovici, Cameron 2006). ‘It records some tremendous catastrophe that happened to Egypt’, says Prof. Donald Redford, the archaeologist (Ibid.). ‘We aren’t quite clear what it was but it involved rain and thunder and lightening, such a storm that rarely happens in northeastern Africa. I mean that’s a dry area’ (Ibid.). For this reasons, the stele has been known as the Tempest or Storm Stele (“Tempest Stele” 2020). Apart from ravaging storms, it also confirms that Egypt was enveloped in darkness and that statues of its gods were toppled to the ground, which may have happened due to a sequence of severe earthquakes (Jacobovici, Cameron 2006).

Wall painting representing foreigners’ procession scene in the tomb of Hatshepsut’s chief architect, Senenmut, (TT 71). The gift-bearers looking like Minoans are probably paying a diplomatic tribute to the Queen of Egypt. Depicted objects with such features as bull’s heads are also analogous to those produced in the Aegean region by Minoans. Such imagery would point out to the Egyptian-Minoan peaceful trade relations (dated by an archaeologist, R. W. Hutchinson, to the Late Minoan IA; 1600 – 1500 BC.). Dates are, however, debated. MacGillivray (2007). Facsimile, after Davies 1936: Pl. XIV. Source: U. Matić (2014); fig. 3, p. 238.

Such ancient records are usually pinpointed to the Eighteenth Dynasty, between the second part of the sixteenth and first part of the fifteenth century BC. But are these records dated correctly? If the stele had been really created by Ahmose and it talks about the Thera eruption, that would place it during the reign of the pharaoh, which is believed to have happened between 1550/49 and 1524 BC, or even twenty years earlier (MacGillivray 2007; “Ahmose I” 2020), which in turn, corresponds to the Late Minoan IA period (1600-1500 BC.). On the other side, Hatshepsut’s exact time of reigning is similarly unclear but usually estimated for the first half of the fifteenth century, sometimes between 1504-1483 or 1478-1458 BC. (MacGillivray 2007; “Hatshepsut” 2020), which mostly fell in the Late Minoan IB period (1500-1450 BC). If there are such discrepancies in dating the ruling of particular Egyptian kings, it is also highly probable some ancient texts are either wrongly ascribed (Ahmose’s stela refers just to a pharaoh, not Ahmose himself) or their date was estimated incorrectly (Jacobovici, Cameron 2006).

Fresco from the tomb of Khnumhotep III in Beni Hassan shows a group of Semitic people, possibly Canaanite merchants, arriving in Egypt. They are thought to be related culturally to the dynasty that called itself the Hyksos. De Agostini Picture Library/G. Sioen/ Bridgeman Images. Source: Andrew Curry (2018). “The Rulers of Foreign Lands”. In: Archaeology.

Moving back to the seventeenth century BC., before Egypt’s consolidation by the Eighteenth Dynasty, it was the Egypt’s dark period (Wengler 2009). The kingdom of Egypt was split in two (Ibid.). The northern region (the Nile delta) was ruled by the Hyksos, foreign invaders from Asia Minor (Ibid.). The time that followed brought economic decline and serious unrest (Ibid.) The rule of the Hyksos kings for long had reminded a trauma in the Egyptian minds (Ibid.). Did that period overlap with the volcano eruption on Thera?

Geologists make their way

For years now, doubts have been growing among scientists about the exact date of the eruption (Wengler 2009).

The reconstructed South Propylaeum of the palace of Knossos, Crete. Copyright©Archaeotravel.

On Santorini, colossal rocks were hurled through the air by the last great eruption of the Bronze Age (Wengler 2009). Between these rocks, a geologist and student of Prof. Friedrich’s, Tom Pfeiffer, found in 2003 – as both geologists say – a critical evidence buried beneath the layers of lava (Wengler 2009; Volcano Discovery 2020). It was an olive branch of a tree smashed by Thera’s eruption (Wengler 2009). Around it, there were remains of olive leaves, twigs and olive stones, which signifies the tree was alive at the time of eruption (Ibid.). As it was an organic material, the remnants were carbon-dated (Ibid.). The moment, the olive branch died would mean the exact date of the volcanic eruption (Ibid.). Since the time of previous results, Prof. Friedrich obtained in 1980s, he has been convinced that the once accepted date of 1500 BC. for the eruption should be officially pushed back a hundred years (History Channel 1980s; Wengler 2009). Moreover, if the previous results had been confirmed by the results obtained by a recently found branch, the new timing would have been unchallengeable (Wengler 2009). Having conducted comparative tests, the geologists have received results confirming that the eruption took place in the seventeenth century BC. and not in the sixteenth century BC. or later (Ibid.). Accordingly, Santorini exploded somewhere between 1620 and 1600 BC (Ibid.). As Prof. Friedrich claims the confirmed date of the tree should have huge consequences for future research and for the understanding of ancient history in general (Ibid.).

Pumice deposit on Santorini, Greece, showing the holes in the pumice where remnants of an olive tree were recovered in 2003. They were found by Tom Pfeiffer, a student of Prof. Friedrich’s in Geology. This organic material allowed another radiocarbon dating of the volcano eruption back to the seventeenth century BC. The results, however, have again been debated. Photo and caption source: Volcano Discovery (2020) “Illustrated Glossary: Plinian eruption. Volcanology”. In: Volcano Discovery. Source: USGS.

Similar date has also been obtained by the soil specialist, Prof. Hendrik Bruins, who has studied Palaikastro’s deposits, which were accumulated by the tsunamis that had smashed the northern coast of Crete (Lilley 2006). He has radiocarbon-dated the cattle bone found on the beach in the deposit (Ibid.). According to the received results, the cattle bone comes from around 1600 BC. (Ibid.) For Prof. Bruins, who has been convinced that the Thera’s eruption took place around 1600 BC., it proves that the chaotic deposit is the result of the tsunami generated by the outbreak of the volcano (Ibid.). Thera’s eruption also produced “enormous volumes of ash and sulphuric acid aerosols which [usually] reduce atmospheric temperatures and may be detected in tree rings as years of slow growth” (Castleden 1998-2001:191). Forensic science and ancient records are also based on these dense clouds of ash across the Middle East and around the world (Westbrook 1995).

Steep volcanic cliffs coming down to the Aegean Sea, Santorini. Copyright©Archaeotravel.

And they also pinpoint the years between 1628-1626 BC. to Thera’s eruption (Westbrook 1995). Although there is a difference of around thirty years between several independent studies, it is still the seventeenth century BC. that they identify (Westbrook 1995; Castleden 1998-2001:191). Thera’s ash has also been found on the Nile, which is traced back to the same time period, like a fingerprint (Westbrook 1995). “[Also] an independent study of Irish bog oaks [has] revealed that 1628-1626 BC. were very poor growth years. […] A search for acidity peaks in ice cores taken from the Greenland ice sheet failed to produce anything perceptible for 1500 BC., but revealed acidity peak for 1645 BC., which some eagerly identified as evidence of an early date for the Thera eruption” (Castleden 1998-2001:191).

Who is closer to the truth?

“In spite of the strenuous lobbying of a seventeenth-century BC. date, the evidence in its favour is inconclusive. To begin with, the eruptions are not the only cause of narrow tree rings: weather patterns vary for a great many reasons. […] From Thera itself comes a different kind of evidence. […] Some radiocarbon dates for the destruction level of Thera are too old for the […] eruption date. Charcoal from a Minoan hearth in the Athinios quarry in 1979 was dated to 1800 BC.; fava beans found in  jug in Building 4 produced a date of 1700 BC. It has been claimed that [these] increasing numbers of radiocarbon dates favour the older date […] In fact, the average of over twenty radiocarbon dates from Akrotiri is 3200 BP, which rather calibrates to 1500 BC. (Castleden 1998-2001:191).

Charlotte Pearson analyzed annual tree rings from bristlecone pines and Irish oak to more accurately estimate the date of the Thera eruption. Photo by Bob Demers/UA News. Photo source: Mari N. Jensen, UA College of Science (2018). “Dating the ancient Minoan eruption of Thera using tree rings” In: UA College of Science.

It is also worth to note that there can be some inaccuracies in standard carbon dating, leading to further mistakes in estimating an exact date for archaeological finds (Gorey 2018). “Research conducted by Cornell University [in 2018] could be about to throw the field of archaeology on its head with the claim that [due to] a number of inaccuracies in commonly accepted carbon dating standards, […] many of […] established historical timelines are thrown into question, potentially needing a re-write of the history books” (Ibid.).

In 2018, further attempts of dating Thera eruption have been conducted using tree rings.

The rings in trees that were alive at the time of the eruption may be a dating source able to settle the debate from conflicting archaeological and radiocarbon analyses. Photo by Garry Knight (2015).  Creative Commons Attribution 2.0. “Age In Double Figures?” Wikimedia Commons. Michelle Starr (2018). “The Date of The Legendary Volcano Explosion of Thera Has Finally Been Traced”. In: Science Alert.

According to University of Arizona-led research, “[new] analyses that [have used] tree rings could settle the long-standing debate about when the volcano Thera erupted by resolving discrepancies between archaeological and radiocarbon methods of dating the eruption, according to new research. […]  ‘It’s about tying together a timeline of ancient Egypt, Greece, Turkey and the rest of the Mediterranean at this critical point in the ancient world – that’s what dating Thera can do’, said lead author Charlotte Pearson, an assistant professor of dendrochronology at the UA Laboratory of Tree-Ring Research. ‘What we can say now is that the radiocarbon evidence is compatible with the archaeological evidence for an eruption of Thera in the 16th century BC’., Pearson said” (Jensen 2018).

Is it a compromise?

The date of Thera volcanic eruption is regarded as crucial as it “has far reaching consequences in the archaeology of the Aegean, Egypt and the Levant, and the understanding of their interconnections” (Jensen 2018). This is why the fierce debate between the two camps, mainly between archaeologists and geologists has still been going on. Nevertheless, the UA Laboratory of Tree-Ring results have offered a provisional compromise.

Analyses that use tree rings could settle the long-standing debate about when Thera erupted by resolving discrepancies between archaeological and radiocarbon methods of dating the volcano eruption, according to new University of Arizona-led research
(Jensen 2018). Material source: Bob Demers (2018). “Ancient sentinels and the secrets locked away in their tree-rings”. In: University of Arizona. UA News. Source: Youtube.

“Archaeologists have estimated the eruption as occurring sometime between 1570 and 1500 BC. by using human artifacts such as written records from Egypt and pottery retrieved from digs. Other researchers estimated the date of the eruption to about [1600-1650] BC. using measurements of radiocarbon, sometimes called carbon-14, from bits of trees, grains and legumes found just below the layer of volcanic ash. […] By using radiocarbon measurements from the annual rings of trees that lived at the time of the eruption, the UA-led team dates the eruption to someplace between 1600 and 1525” (Jensen 2018).

Clay model from Palaikastro, Crete, representing three female figures dancing with their arms stretched, in a circle, to the accompaniment of a lyre held by a woman in the middle. Preserved by the Archaeological Museum of Heraklion. Copyright©Archaeotravel.

Although the results are more in favour of later dates for the eruption, as an estimated “time period overlaps with the 1570-1500 date range from the archaeological evidence” (Ibid.), the highest point of the same results points to the date of 1600 BC., which has been, in turn, proposed by geologists.

If standard methods fail, scientists count on legends

In the matter of Thera eruption the scientific research still remains unclear. Although a century as the time difference range for the eruption of Thera does not seem significant for a geology, it rather counts in terms of history of the region. In this case, with just few written records as their guide, scholars usually have no choice but to use legends as launching pads for their studies (Masjum 2006).

Fairy-like colours of the island of Santorini. On the horizon the tiny island, Nea Kameni, situated within the flooded caldera. Copyright©Archaeotravel.

‘When volcanologists are trying to reconstruct an ancient eruption, [they] use everything [they] can, all the available data and certainly, there are a lot of collaboration between volcanologists, historians and archaeologists’, says Dr. Rosaly Lopes Gaultier (Masjum 2006). ‘In Santorini, for example, it turned out to be a great collaboration because archaeologists can tell the things helping to date the eruption, while other scientists studying the volcano can tell more about the effects and sequence of events. [Hence] it ends up tying it all together. And you even look at legends and stories’ (Ibid.).

So do I …

Featured image: After the volcanic eruption, the circular shape of the island of Thera had been shaped into a semi-circular crescent, which is clearly visible in the aerial photo taken from the plane. Copyright©Archaeotravel.

By Joanna
Faculties of English Philology, History of Art and Archaeology.
University of Silesia in Katowice, Poland;
Cardinal Stefan Wyszyński University in Warsaw, Poland;
University College Dublin, Ireland.

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