When Xerxes prepared for the invasion of Greece, he could draw not only on the impressive wealth and manpower which his Empire afforded but also, where special problems required it, on the considerable expertise available to him. The construction of a bridge across the Hellespont, and the digging of a ship canal across the Mount Athos peninsula at its narrowest point involved the use of all these resources. The bridge has long gone, but traces of the canal can still be seen on the isthmus between Nea Roda on the northern and Tripiti on the southern shore, in the narrowest section of the Mount Athos peninsula. It represents not only the most impressive surviving monument of Persia's short-lived imperial presence in Europe, but also one of the most important pieces of ancient marine communication engineering anywhere. That it should have attracted the attention of classical writers from Herodotus onwards, and of scholars and travellers in more recent times, is not surprising. It is however remarkable that modern archaeological research has passed it by completely. Yet there are not many cases where a detailed technical report from ancient times could be so fruitfully linked with modern methods of investigation -providing, incidentally, a useful test case for the much discussed veracity of Herodotus.To obtain information about the canal, three lines of evidence are available to us. There are, firstly, statements by classical writers, especially by Herodotus (VII, 22-24, 37> 122); 1 secondly, reports by more recent visitors, including the one by Col. Leake 2 who visited the site in 1806, and more in particular the description accompanied by a survey map, offered by Choiseul-Gouffier 3 (who discusses what he saw in 1766) and the detailed account and plan published by Spratt; this latter represents the state of things encountered by him in 1838, when he was detailed by Commander Graves of H.M.S. Beacon, in which he was then serving as a lieutenant, to measure across the isthmus of Mount Athos at the spot where the canal was cut by Xerxes. 4 Lastly, there is the testimony offered by ocular inspection now, and by air photos of various quality and date: detailed maps of the canal zone by the Greek authorities are in preparation but are not yet available.The reasons which impelled Xerxes to order the digging of the canal was, we are told, his desire to avoid a repetition of the disaster which struck the Persian fleet led by Mardonius when it tried to round the Mount Athos headland in 492 B.C. Sailing around this headland has indeed remained a potentially dangerous operation for small craft, particularly since adverse winds and currents may prevail during considerable parts of the year. Both Choiseuil-Gouffier and Leake refer to this fact; indeed the latter reports that he 1 For a list of classical and later authorities who have 3 M.G.A.P. de Choiseul-Gouffier, Voyage pittoresque en referred to our subject see E. Oberhummer in RE II
