Where, How and When

Herodotus preserves a curious story about an event which happened in the aftermath of the Battle of Salamis. Xerxes, the Persian king, did not linger in Greece after the defeat of his fleet but high-tailed it back to safety in the city of Sardis. He was accompanied in his undigified retreat by 60,000 Persian troops under the command of Artabazus and once the king was safe, Artabazus and his troops returned to Greece where Mardonius and another 300,000 were planning to subjugate Greece on land.

However by the time Artabazus was back in Greece he found that Mardonius had gone into winter quarters, which meant that there was no hurry about joining him. He also found himself in the middle of a revolt, for as soon as the locals realised what had happened at Salamis, they turned against their new overlords. The two main cities in that part of Greece were Olynthus and Potidaea and Artabazus made short work of Olynthus, massacring its inhabitants. He then turned his attention to Potidaea.

In preparation for his attack on Greece, Xerxes had caused a canal to be dug across the Mt Athos peninsula at its narrowest point. He might have wished to do the same across the next of the three peninsulas that hang down into the Aegean Sea like fingers, but the Dragoudelios Peninsula is not only wider than the other two but its has a mountainous spine and hewing a canal through the rocks was not possible in the days before dynamite.

Aerial view of Potidaea
Ironically, there is now a canal through the middle of modern Potidaea.

When it came to the third, the Kassandra Peninsula, although it was even flatter and narrower than the Mt Athos one, the ideal place for a canal was occupied by a walled city whose inhabitants, we may be sure, made their feelings about a canal through their agora abundantly clear. It was this same location astride the narrowest part of the peninsula which baffled Artabazus and his troops, because they could only attack the city from one side and had no hope of succeeding with a siege because the farms in the rest of the peninsula supplied the city with food.

Artabazus' first attempt at a solution was to subborn one of the garrison.

Artabazus pressed the siege of Potidaea all the more unremittingly; and was pushing his operations with vigour, when Timoxenus, captain of the Scionaeans, entered into a plot to betray the town to him. How the matter was managed at first, I cannot pretend to say, for no account has come down to us: but at the last this is what happened. Whenever Timoxenus wished to send a letter to Artabazus, or Artabazus to send one to Timoxenus, the letter was written on a strip of paper, and rolled round the notched end of an arrow-shaft; the feathers were then put on over the paper, and the arrow thus prepared was shot to some place agreed upon. But after a while the plot of Timoxenus to betray Potidaea was discovered in this way. Artabazus, on one occasion, shot off his arrow, intending to send it to the accustomed place, but, missing his mark, hit one of the Potidaeans in the shoulder. A crowd gathered about the wounded man, as commonly happens in war; and when the arrow was pulled out, they noticed the paper, and straightway carried it to the captains who were present from the various cities of the peninsula. The captains read the letter, and, finding who the traitor was, nevertheless resolved, out of regard for the city of Scione, that as they did not wish the Scionaeans to be thenceforth branded with the name of traitors, they would not bring against him any charge of treachery. Such accordingly was the mode in which this plot was discovered.
Herodotus: History VIII.128

I'm not sure what Artabazus' back-up plan was, but after a weary three months of winter fighting a miracle happened - and the Persians were not slow to take advantage of it.

After Artabazus had continued the siege by the space of three months, it happened that there was an unusual ebb of the tide, which lasted a long while. So when the barbarians saw that what had been sea was now no more than a swamp, they determined to push across it into Pallene, And now the troops had already made good two-fifths of their passage, and three-fifths still remained before they could reach Palline, when the tide came in with a very high flood, higher than had ever been seen before, as the inhabitants of those parts declare, though high floods are by no means uncommon. All who were not able to swim perished immediately; the rest were slain by the Potidaeans, who bore down upon them in their sailing vessels. The Potidaeans say that what caused this swell and flood and so brought about the disaster of the Persians which ensued therefrom, was the profanation, by the very men now destroyed in the sea, of the temple and image of Poseidon, situated in their suburb. And in this they seem to me to say well. Artabazus afterwards led away the remainder of his army, and joined Mardonius in Thessaly. Thus fared it with the Persians who escorted the king to the strait.
Herodotus: History VIII.129

The Mediterranean is known as the tideless sea, a statement which is not entirely accurate. Depending on where you are, the tide can vary from four and a half feet near Sfax in Tunisia, to a mere eighteen inches at Venice, while in the Aegean there is virtually no tide at all. Herodotus' statement that the Persians were trapped by an extra low tide is, therefore, entirely wrong.

Japanese tsunami in 2011
The effects of the Japanese tsunami of 2011.

The first time I read this tale my mind was irresistably drawn to the phenomenon of the tsunami (commonly and incorrectly known as a "tidal wave"). As we know all too well these days, after the 2004 Christmas Tsunami that devastated the countries bordering on the Indian Ocean, and the 2011 Japanese Tsunami that wrecked their Fukushima nuclear power station, a huge withdrawal of the sea followed by a crashing wave that sweeps all before it, is more or less diagnostic for a tsunami.

There's just one problem: a tsunami is always associated with an earthquake. The earthquake may be so far away that it is not felt in every place affected by the water, but there is still an earthquake. That being so, it is curious that Herodotus does not mention it, if for no other reason than to appeal to his readers' knowledge. "That was the earthquake that shook Athens and rattled Thebes", for example, would help to identify the occasion to his readers.

Herodotus specifically links the unusual behaviour of the sea to the god Poseidon (often identified with Neptune). Poseidon was the god of the sea - hence the use of an unusual tide to avenge his profaned temple - but he was also the god of earthquakes, so if there had been an earthquake at this time I think we can be confident that Herodotus would have mentioned it!

However if the earthquake had been some distance away, so distant that it was not felt in Greece other than by the tsunami, then it is strange that only the city of Potidaea was affected. The power and height of a tsunami is directly linked to distance from the point of origin. If the triggering earthquake had been in - say - Egypt, we would expect that a sea port like Athens and Piraeus would be even more affected by the tsunami than Potidaea: It is 580 miles in a direct line from Egypt to Athens, but Potidaea is another 165 miles further on!

Meteotsunami on Mali Losinj.
The flooded waterfront of Mali Losinj in Croatia which was hit by a meteotsunami on August 15, 2008.

On the whole, then, I find the tsunami explanation unconvincing. I am also disinclined to attribute the disaster to the wrath of Poseidon! Which left me scratching for an explanation until I started to read a book called Tide by Hugh Aldersey-Williams. In his second chapter he has a whole section about "Mediterranean tides" and he mentions a phenomenon of which I had not previously heard.

Several places in the Mediterranean occasionally experience the rissaga, a kind of miniature tsunami generated when severe wearther produces a sudden change in the pressure of the atmosphere bearing on the sea surface, which in turn causes a substantial 'tide' to rise and fall again within the space of perhaps no more than ten minutes.
Hugh Aldersey-Williams: Tide p. 39, 30

I am not sure why Mr Aldersey-Williams chooses to use a Catalan term for something which is better known by the scientific name of meteotsunami - that's the name you'll need to use to find a description of the phenomenon in Wikipedia. There you will learn that the water can be displaced for a period of "several minutes to several hours", a length of time sufficient to lead the Persians to rally their troops and set off over the exposed sea bed, only to be caught by the returning waters.

If you hunt around on YouTube you can even find video of meteotsunami, including a news report of one that struck the island of Mallorca with sufficient force to carry off and drown a German tourist! Elsewhere on the web you can find mention of a 10' wave generated on Lake Michigan which hit Chicago in 1954 and drowned seven people.

This, it seems to me, is the most likely explanation for Herodotus' story of the miraculous deliverance of Potidaea, for Artabanus seems to have been so discouraged by the event that he abandoned the siege and the citizens of Potidaea were able to maintain their precarious independence until victory at the battle of Plataea put a final end to the Persian menace.

However there is another miraculous receding and return of a sea that also springs to mind - the crossing of the Red Sea. I entirely agree with my father, who discovered a nautical chart of the northern end of the Gulf of Suez which showed a sand bar extending from Adabiyeh Point to the other side of the gulf. You can see me giving a full explanation for the identification on this site on the NWTV website.

The depth of water over the sand bar is 27' at its deepest. The Bible attributes the parting of the sea to a miraculous strong wind.

Then Moses stretched out his hand over the sea, and all that night Yahweh drove the sea back with a strong east wind and turned it into dry land. The waters were divided and the Israelites went through the sea on dry ground, with a wall of water on their right and on their left.
Exodus 14:21, 22

That is conceivable: Hurricane Katrina swept a 30' wave over New Orleans and I could easily imagine a strong wind driving the water in the Gulf of Suez southwards and uncovering the sand bar. The only trouble is that according to Moses the wind was coming from the east - the wrong direction - and a hurricane force wind blowing sand in your face and tearing at your clothing as you tried to force your way into it would not exactly conduce to the crossing!

However the mention of a strong wind does point to unusual meterological conditions. Unfortunately Moses did not have a barometer with him to measure the atmospheric pressure or any changes in that pressure; he didn't even have an anenometer to tell us the wind speed, so we cannot be entirely sure of what was going on - but is it possible that a meteotsunami was somehow involved in the crossing of the Red Sea?

The water retreats for several hours or even most of the night, leaving the sand bar exposed, which the Israelites cross in a rush and then, as dawn breaks, the Egyptians discover what is going on and set out in pursuit, only to have the meteotsunami return with a rush that sweeps them all into oblivion.

The crossing of the Red Sea
Cecil B. de Mille's imaginative and dramatic vision of the crossing of the Red Sea.

The main objection to such a scenario is that it removes the towering walls of water so beloved of Cecil B. de Milles and other artists. Instead of trudging between high walls of water and encountering surprised sharks along the way, we have to picture the Israelites marching across a causeway with expanses of deep water on either side, water that protected them from their pursuers as effectively as walls, but were not actually vertical cliffs of water.

Well, that's all speculation and if anyone prefers to think that it was a direct miracle, I shan't quarrel with him. For those who believe that God usually works through natural means and the miracle lies in the place and timing of the event, this is a possible explanation.

© Kendall K. Down 2019