Just as he had expected, he saw the grinning face of Tony Fitzpaine.

Fitzpaine was the arrogant, aristocratic youth James had knocked into the river after Haight’s lecture to the Archaeological Society. Finding out that Fitzpaine was on the trip had been something of a shock to James and, ever since confronting him on the Channel ferry, Fitzpaine had gone out of his way to get up James’s nose.

James let it go, and chose to ignore him. It was too hot to risk getting worked up about anything.

Haight told the boys to be more careful and organized them into three work parties.

For a couple of hours James helped out, kneeling in the dirt alongside Perry Mandeville, and as he worked his mind was free to think.

Last night, as he’d been unpacking his suitcase, he’d found a letter. Charmian had stuffed it into his pocket when he was leaving her cottage and in his excitement he had forgotten all about it.

He’d sat down on his camp bed, slit the envelope open and taken out an untidily folded sheet of notepaper. He’d recognised the handwriting immediately: thin and slanting and spidery, it was from Mr Merriot, his classical tutor at Eton.

Dear James,

Forgive me for writing to you in the holidays, old chap. I’m sure the last thing you want to be thinking about right now is school, but I thought you might be interested in this. You asked me in private business the other day if the Roman numerals MM held any significance. At the time I could think of nothing, but last night I was having dinner with my colleague Mr Cooper-ffrench. I don’t think he’s forgotten about meeting your formidable aunt, by the way!

Our conversation turned to Roman history, as it so often does with Cooper-ffrench, and he mentioned a secret Italian society known as the Millennaria.

If you’ll permit me a short history lesson, I’ll fill you in on some of the background. While we teach a great deal about the ancient Romans, there’s very little room left in your poor aching noodles for more recent Italian history. But, to be brief, a hundred years ago there was no country called Italy, as such. That is to say, the area we now know as Italy was made up of various rival city-states, many of them governed by foreign rulers. Then, in the first half of the nineteenth century a nationalist movement sprang up. The idea was to unite the land into one country and boot out all the foreigners.

Well, the Italians have always been fond of secret societies and spies and skulduggery, so, rather than simply form an army, the nationalists created a great number of underground groups instead, whose aim was to spread the word about unification and generally stir things up. Most of it came to nothing until, with the help of a great general called Garibaldi, a movement called the Risorgimento eventually succeeded in uniting the whole country in the 1870s. They created what we now know as Italy, under one king – Victor Emmanuel of Sardinia (where you’re off to, I believe).