Roman holidays

You might begin this holiday in Orkney, which the Greeks barely knew except through the reports of a certain Pytheas, a man from Marseilles whom not everyone at the time (or since) has believed.

Then slip down the east coast of Britannia, noting that the Wash seems to have been broader 2,000 years ago and that a large chunk of Kent was accessible only by sea.

By now you have missed York, Roman Eburacum, and its 1700th aniversary celebrations this year (see Odds on Italy and Be Nice to Our Emperor below) of the acclamation of Constantine as Emperor of Rome.

But, since this is a virtual holiday, you can go back to York if you want to.

I am not travelling through Europe. I am only thinking ancient geography, at the beginning of a miraculous book which maps the world as it was for our founders.

So I can leap down to where Paris is today and find Lutetia, not a big, bold-lettered place at the time when Caesar was dividing Gaul into three parts but still in this period the favourite home of the Emperor Julian, who tried briefly to undo what Constantine had done.

And then, with the turn of a page, I am off to Bohemia (Were the Ancient Bohemians bohemian? There is a mildly obscene passage in Plautus which suggests that they might have been).

Or, if I want to pretend a plausible journey rather than zig-zag as the atlas sequence encourages, I can go south to Rome itself.

Rome is the centre of this ancient world, now mapped with more of the geographer's accuracy than ever before. The Barrington Atlas took some $5 million and ten years to produce and employed a greater army of international measurers, supervisors and assessors than any ancient general, or any potentate who might have made practical use of it, could have even thought of assembling.

Maps make madmen of us all. No modern scholar can map a single square mile of the Peloponnese without some other scholar saying that he or she is mad, misinformed, politically motivated and often much worse. The Barrington Atlas comes equipped with CD-Roms and websites on which the editors can argue their case and their critics can throw theodolites at the mistakes.

This atlas does not show sites where things merely happened, like battles, even very big and important battles. It does not show where things have been discovered or what those things might tell us about who lived in the land described by these large, luxurious, pale-pink-and-green pages. It shows what the land was like.

Those who want to argue about something else, about whether Sparta is more a spattering of villages than a town or whether the index makes it easy enough to distinguish Athens (Greece) from Athens (various other places) can take themselves elsewhere on-line. For the rest of us, particularly if we have lost our elderly copies of those much more limited predecessors, Hammond's and Grant's atlases, the book is blessedly separate from the debates.

The range covers the full extent of the classical world.

My imaginary trip that began above the Scottish Highlands can end in the Caucasus or on the plains of the Upper Nile. I can leave Athens for Sardis and follow the wanderings of Xenophon's Ten Thousand until they shout, Thalatta, Thalatta, the Sea, the Sea; and I can make the trip without disturbance from what has grown up along the ways since 400 BC.

I can leave Rome and follow Horace's route to Brindisi as he describes it in the Fifth Satire; the maps do not show the noisy frogs, lazy boatmen and fraudulent priests but at least we can see the way clear from the clutter of succeeding centuries.

These are magic maps, a holiday on every page.