Dillen enlarged the right-hand disc. “This one came up with the French excavations last year.”
“Date?” Hiebermeyer demanded.
“The palace was abandoned in the sixteenth century BC, following the eruption of Thera. Unlike Knossos, it was never reoccupied. So the discs may have been lost about the same time as your shipwreck.”
“But they could date earlier,” Jack suggested.
“Much earlier.” Dillen’s voice had a now-familiar edge of excitement. “Costas, what do you know about thermoluminescence dating?”
Costas looked perplexed but replied enthusiastically. “If you bury mineral crystals they gradually absorb radioactive isotopes from the surrounding material until they’re at the same level. If you then heat the mineral the trapped electrons are emitted as thermoluminescence.” Costas began to guess where the question was leading. “When you fire pottery it emits stored TL, setting its TL clock back to zero. Bury it and the pottery begins to reabsorb isotopes at a set rate. If you know this rate as well as the TL level of the surrounding sediment you can date the clay by heating it and measuring the TL emission.”
“How precisely?” Dillen asked.
“The latest refinements in optically stimulated luminescence allow us to go back half a million years,” Costas replied. “That’s the date for burnt hearth material from the earliest Neanderthal sites in Europe. For kiln-fired pottery, which first appears in the fifth millennium BC in the Near East, combined TL-OSL can date a sherd to within a few hundred years if the conditions are right.”
Costas had built up a formidable expertise in archaeological science since joining IMU, fuelled by his conviction that most of the questions Jack posed about the distant past would one day be resolved by hard science.
“The second disc, the one discovered last year, was fired.” Dillen picked up a sheet of paper as he spoke. “A fragment was sent to the Oxford Thermoluminescence Laboratory for analysis, using a new strontium technique which can fix the date of firing with even greater accuracy. I’ve just had the results.”
The others looked on expectantly.
“Give or take a hundred years, that disc was fired in 5500 BC.”
There was a collective gasp of astonishment.
“Impossible,” snorted Hiebermeyer.
“That’s a little earlier than our wreck,” Costas exclaimed.
“Just four thousand years earlier,” Jack said quietly.
“Two and a half millennia before the palace at Knossos.” Hiebermeyer was still shaking his head. “Only a few centuries after the first farmers arrived on Crete. And if that’s writing, then it’s the earliest known by two thousand years. Near Eastern cuneiform and Egyptian hieroglyphics don’t appear until the late fourth millennium BC.”
“It seems incredible,” Dillen replied. “But you’ll soon see why I’m convinced it is true.”
Jack and Costas watched the screen intently as Dillen loaded a CD-ROM into his laptop and linked it to the multimedia projector. The picture of the pottery discs was replaced by the symbols arranged as a column, each one fronting groups clustered together like words. They could see he had been applying similar techniques of analysis to those he had used to study the Greek script on the papyrus.
Jack reactivated the teleconference module and they were once again face to face with Dillen and Hiebermeyer two hundred miles away in Alexandria.
“Those are the symbols from the Phaistos discs,” Jack said.
“Correct.” Dillen tapped a key and the two discs reappeared, this time in the lower left-hand corner. “The thing that has most baffled scholars is that the discs are virtually identical, except in one crucial respect.” He moved a cursor to highlight various features. “On one side, what I call the obverse, both discs have exactly one hundred and twenty-three symbols. Both are segmented into thirty-one groupings, each comprising anywhere from two to seven symbols. The menu, if you like, is the same, comprising forty-five different symbols. And the frequency is identical. So the Mohican head occurs thirteen times, the marching man six times, the flayed oxhide eleven times, and so on. It’s a similar story on the reverse, except with thirty words and one hundred and eighteen symbols.”
“But the order and groupings are different,” Jack pointed out.
“Precisely. Look at the first disc. Walking man plus tree, three times. Sun disc plus Mohican head, eight times. And twice the entire sequence of arrow, baton, paddle, boat, oxhide and human head. None of these groupings occur on the second disc.”
“Bizarre,” Costas murmured.
“I believe the discs were kept together as a pair, one legible and the other meaningless. Whoever did this was trying to suggest that the type, number and frequency of the symbols were what was important, not their associations. It was a ruse, a way of diverting attention from the grouping of the symbols, of dissuading the curious from seeking meaning in the sequence.”
“But surely there is meaning in this,” Costas cut in impatiently. He clicked on his mouse to highlight combinations on the first disc. “Boat beside paddle. Walking man. Mohican man always looking in the same direction. Sheaf of corn. The circular symbol, presumably the sun, in about half the groupings. It’s some kind of journey, maybe not a real one but a journey through the year, showing the cycle of the seasons.”
Dillen smiled. “Precisely the line taken by scholars who believe the first disc contains a message, that it was not just decorative. It does seem to offer more sense than the second disc, more logic in the sequence of images.”
“But?”
“But that may be part of the ruse. The creator of the first disc may have deliberately paired symbols which seem to belong together, like paddle and boat, in the hope that people would attempt to decipher the disc in just this way.”
“But surely paddle and boat do go together,” Costas protested.
“Only if you assume they’re pictograms, in which case paddle means paddle, boat means boat. Paddle and boat together mean going by water, seafaring, movement.”
“Pictograms were the first form of writing,” Hiebermeyer added. “But even the earliest Egyptian hieroglyphs were not all pictograms.”
“A symbol can also be a phonogram, where the object represents a sound, not a thing or an action,” Dillen continued. “In English we might use a paddle to represent the letter P, or the syllable pa.”
Costas slowly nodded. “So you mean the symbols on the discs could be a kind of alphabet?”
“Yes, though not in the strict sense of the word. The earliest version of our alphabet was the north Semitic precursor of the Phoenician alphabet of the second millennium BC. The innovative feature was a different symbol for each of the main vowel and consonant sounds. Earlier systems tended to be syllabic, each symbol representing a vowel and a consonant. That’s how we interpret the Linear A writing of the Minoans and the Linear B of the Mycenaeans.” Dillen tapped a key and the screen reverted to the image of the golden disc. “Which brings us to your wreck find.”
He magnified the image to show the mysterious symbol deeply impressed in the centre of the gold disc. After a pause it was joined by another image, an irregular black slab covered with three separate bands of finely spaced writing.
“The Rosetta stone?” Hiebermeyer looked baffled.
“As you know, Napoleon’s army of conquest in Egypt in 1798 included a legion of scholars and draughtsmen. This was their most sensational discovery, found near ancient Saïs on the Rosetta branch of the Nile.” Dillen highlighted each section of text in turn, beginning at the top. “Egyptian hieroglyphics. Egyptian demotic. Hellenistic Greek. Twenty years later a philologist named Champollion realized these were translations of the same narrative, a trilingual decree issued by Ptolemy V in 196 BC when the Greeks controlled Egypt. Champollion used his knowledge of ancient Greek to translate the other two texts. The Rosetta Stone was the key to deciphering hieroglyphics.” Dillen tapped a key and the stone disappeared, the screen again reverting to the image of the golden disc.