Southernmost of the Cyclades, the Greek island group of Thera is often called Santorini, a name given it by  by Venetian conquerors in 1207.  Thera is also the focus of myriad theories, some scientific, some not so scientific, and some downright loony.  Most link the colossal eruption of Thera approximately 3500 years ago, the largest known to have occurred within recorded history, to some well-known historic event in the Late Bronze Age.  Among these events:
  • The destruction of Minoan civilization on Crete, or at least enough destruction to eclipse Cretan domination and make way for the rise of Mycenean domination, as well as the decline of Linear A and the rise of Linear B.
  • Similar to the above, many people use the wreck of Cretan civilization, or of a city on the island itself, as a historical kernel for the story of the destruction of Atlantis, a cautionary tale inserted by Plato into his dialogues Timaeus and Critas. When I first wrote this, the city I would have bet on would have been Akrotiri on the coast of the island. Akrotiri is the principal Bronze Age archaological site on Thera. However, a remarkable fresco has recently been found in Akrotiri, depicting a city on an island in what looks remarkably like Thera's lagoon. Thera appears to have been much more important to Bronze Age Greece than originally thought, a major trading center for commodities such as olive oil between the islands. This is surprisingly similar to Plato's description of Atlantis. Not only that, when the magma chamber beneath Thera collapsed, anything in the lagoon would have fallen into the new deep sea that formed.
  • Many events in Exodus, such as
    • the plagues of Egypt, each given a plausible geological explanation.
    • the parting of a Sea of Reeds allowing the Hebrews to cross, followed by the destruction of Pharaoh's pursuing army, presumably caused by Thera's tsunami.
    • the appearance of God as a pillar of fire by day, and a cloud by night.
All of these involve jockeying the date of the event to fit some accepted date for the eruption of Thera.  However, this date is a matter of some controversy.

Archaeologists, using a chronology of the Bronze Age based upon the evolution of pottery styles, have traditionally placed the demise of Minoan civilization at around 1450 BC.  Biblical scholars clung for a long time to a date of 1275 BC for the Exodus, during the reign of Ramses II, although a theory dating it to 1446 BC, during the reign of Tutmosis III, has recently gained wide acceptance.

In the 1990's, a large amount of scientific evidence began to pile up in favor of a much earlier date for the Thera eruption.   During the study of complete tree ring sequences from bristlecone pines in California's White Mountains, a remarkably narrow ring appeared for 1627 BC, exhibiting cell death from severe frost damage.  Very thin rings in modern trees indicate years with very bad growing conditions: Unusually dry or unusually cold. Presumably, a large eruption would have occurred in 1628 BC, the previous year.  Studies of oaks buried in Irish peat bogs, and pollen in Greenland ice cores, also point to a date around 1628 BC.

Naturally, suggesting that the long-accepted pottery timeline is off by nearly 200 years did not sit well with archaeologists.  If Cretan domination of the Aegean ended in 1628 BC and not 1450 BC, the life's work of many archaeologists would have to be substantially revised.  A 1989 conference on the subject of Thera was a firestorm of controversy on the matter, with some accepting the earlier date, others dismissing it and clinging to their potsherds.

The 1628 BC date has gained wider acceptance over the succeeding years; however, the issue is by no means settled.   There is only circumstantial evidence for linking the tree rings to Thera; and it is possible that another unrecorded volcanic eruption, say from Alaska or Siberia, would have caused the unusually cold year of 1627 BC.   On the other hand, Thera's eruption was a really big one, and presumably, another eruption that big would not have escaped geologists' notice.

Starting from tiny bits of knowledge picked up over a lifetime, triggered by a TV show about bristlecone pines, followed by searching the Web for more information,

V.C. LaMarche, Jr. and K.K. Hirschboeck, 1984. "Frost rings in trees as records of major volcanic eruptions", Nature, v. 307, 121-126

"The Changing Face of the Thera Problem", J. V. Luce, Classics Ireland, 1994 Volume 1, transcribed at

Charles Pellegrino, Unearthing Atlantis,  (pages 233-246), transcribed at

"Overview and Assessment of the Evidence for the Date of the Eruption of Thera" in D. A. Hardy and A. C. Renfrew, eds., Thera and the Aegean World III: Proceedings of the Third International Congress, Santorini, Greece, 3-9 September 1989. Vol. III "Chronology" (London: The Thera Foundation 1990) 13-18.
transcribed at

An Introduction to the Book of Exodus, at

Museum of Prehistoric Thera, Greek ministry of Culture,