[3] Herodotus speculates that pride also was a motivating factor: As far as I can judge by conjecture, Xerxes gave the command for this digging out of pride, wishing to display his power and leave a memorial; with no trouble they could have drawn their ships across the isthmus, yet he ordered them to dig a canal from sea to sea, wide enough to float two triremes rowed abreast.
[1] The canal still formed part of the landscape 80 years later as it is mentioned in passing by Thucidydes in The History of the Peloponnesian War from around 400 BC: After the taking of Amphipolis, Brasidas and his allies marched to the so-called Actè, or coastland, which runs out from the canal made by the Persian King and extends into the peninsula; it ends in Athos, a high mountain projecting into the Aegean sea.
[7]The veracity of Herodotus' claims was doubted already in ancient times, but land surveys and geophysical investigations of the peninsula have confirmed the canal's existence.
[1] A British and Greek collaborative geophysical investigation launched in the 1990s found, using seismic survey and sediment analysis, that the canal had crossed the whole isthmus.
[1] Some studies suggest the workers were both regular Achaemenid soldiers and recruited local Balkan people (Thracians and Greeks) with the legal status of kurtaš, who were paid for and fed from the Persian treasury.