Albia dragged back decorum into the conversation: ‘My favourite phrase is Please help; my slave has expired from sunstroke in the basilica!’

Helena smiled. ‘Weil, I was particularly proud of: Can you direct me to an apothecary who sells inexpensive corn-plasters? which then has a follow-up: If I need anything of a more delicate nature, can I trust him to be discreet?’

Uncle Fulvius displayed unexpected good nature, informing Albia in slow phrases, ‘Yes, there are earthquakes in this country, although fortunately most are mild.’

‘Do they cause much damage, pray?’

‘It is always a possibility. However, this city has existed safely for four hundred years . . .’ Albia was having trouble with Greek numbers; she started panicking. The Librarian had listened inscrutably.

When the main dishes came, of course we switched topics. I applied myself politely to local questions. Hardly had I broached how hot was the weather likely to be during our stay, when Aulus interrupted, launching into how he had fared that morning at the Museion. Aulus could be crass. Now the Librarian would assume he had been invited tonight so we could beg a place for Aulus.

Theon glared at the would-be scholar. What he saw would not impress: a truculent twenty-eight-year-old, overdue for a haircut, with so few social graces anyone could see why he had not followed his father into the Senate. No one would guess Aulus had nonetheless done a routine stint as an army tribune and even spent a year in the governor’s office in Baetican Spain. In Athens he had grown a beard like Greek philosophers. Helena was terrified their mother would hear about it. No honest Roman wears a beard. Access to good razors is what singles us out from the barbarians.

‘Decisions about admissions are taken by the Museion - it is out of my hands,’ warned Theon.

‘Not to bother. I used my charm.’ Aulus smiled triumphantly.’ I was accepted straight away’

‘Olympus!’ I let slip. ‘That’s a surprise!’

Theon appeared to think the same. ‘And what do you do, Falco? Here for education or commerce?’

‘Just a trip to visit family and put in some gentle sightseeing.’

‘My nephew and his wife are intrepid travellers,’ beamed Uncle Fulvius. He was no slouch himself at touring, though he kept to the Mediterranean whereas I had been to more remote areas: Britain, Spain, Germany, Gaul . . . My uncle would shudder at those grim provinces, with their heavy legionary presence and absence of Greek influence. ‘Your activities are not unconnected with imperial business, eh, Marcus? And I heard you were involved with the Census not so long ago? Falco is very highly regarded, Theon. So tell us, nephew, who is due for a penetrating audit here?’

Had Cassius not placed himself between us on the dining couches I could have kicked Fulvius. Trust relatives to open their mouths. Up until that point, the Librarian had viewed us as the usual ill-read foreigners wanting to look at pyramids. Now, of course, his gaze sharpened.

Helena helped him to pork-stuffed-two-ways and dealt with it briskly. ‘My husband is an informer, Theon. He did carry out a special investigation into Census avoidance two years ago, but his work in Rome is mainly background checks on people’s intended marriage partners. The public have the wrong perception of what Falco does, though in fact it is commercial and routine.’

‘Informers are never popular,’ Theon commented, not quite sneering.

I wiped sticky fingers on my napkin. ‘Mud sticks. You will have heard about the crooked ones among my colleagues in the past, who pointed out rich men to Nero; he had them hauled into court on trumped-up charges so he could plunder their assets - with the informers taking a cut, of course. Vespasian put an end to that scam - not that I ever dabbled. Nowadays it’s all small beans. Disputing wills for hopeful widows or chasing after runaway partners from debt-ridden small businesses. I help members of the public avoid pain, yet for the world at large my work still has the fragrance of a blocked drain.’

‘So what do you do for the Emperor?’ The Librarian would not let it go.

‘The public is correct. I poke a long stick into noxious blockages.’

‘That takes skill?’

‘Just a strong shoulder and knowing when to hold your nose.’

‘Marcus is being modest.’ Helena was my best supporter. I winked at her wickedly, implying that if we had been couched alongside, I would have given her a squeeze. Against convention - but convention never bothers me. She was wearing dark red, a colour that gave her a luscious glow, with a gold necklace I had bought for her after a particularly profitable mission. ‘He is a first-class investigator with exceptional skills. He works quickly, discreetly and with unfailing humanity’ And he’s all hands, said her dark eyes back to me across the half-circle of couches.

I sent over more private eye-messages to Helena. Theon had spotted something going on, but had not worked out that it was lechery. ‘The noble Helena Justina is not just my wife, but my accountant, business manager and publicist. If Helena decides you need an enquiry agent - good references and cheap rates - then she will prise a commission out of you, Theon!’

Helena then shot us all a beaming smile. ’Oh not this month, darling! We are in Egypt on holiday!’

‘All-seeing Argos never sleeps!’ Now it was Aulus pompously giving the game away. I was surrounded by idiots. No one had any discretion; well, except Cassius, who was so worn out by his exertions all day he had nodded off with his chin on his forearm. Protruding from a wide-sleeved robe of some African design, the forearm was extremely hairy.

‘Classical allusion? Oh really!’ Helena rapped her brother playfully with the end of a shellfish spoon. ‘Marcus promised he would be all mine. He has come away to spend time with me and the little ones.’

I tucked into my foodbowl, looking like an innocent domestic treasure.

Helena then swerved neatly and started polite Smalltalk about the Great Library. Theon ignored Helena. He favoured me with a professional grumble: ‘You might think the Library is the most important institution here, Falco, but for administrative purposes, it counts less than the observatory, the medical laboratory - or even the zoo! I ought to be feted but am harassed at every turn, while others take precedence. The Director of the Museion is by tradition a priest, not a scholar. Yet he includes in his title, ’’Head of the United Libraries of Alexandria”, whereas I - in charge of the most renowned collection of knowledge in the world - am merely its curator and secondary to him. And why should the Pharos be so famous - a mere bonfire at the top of a tower - when the Library is the true beacon, a beacon of civilisation?’

‘Indeed,’ Helena humoured him, ignoring in her turn his exclusion of women. ‘The Great Library, Megale Bibliothcca. should be one of the Wonders of the World. I have read that Ptolemy Soter, who first set out to found a centre of universal scholarship here, decided to collect not only Hellenic literature, but “all the books of the peoples of the world”. He spared neither expense nor effort -’ Theon was clearly unimpressed by her research. Women were not permitted to study in his Library and I reckoned he rarely mingled with them. I doubted it he was married. Helena’s attempts at flattery met only a downcast expression of bad temper and bad grace. The man was hard going. Probably desperate, she jangled an armful of bangles and asked the obvious question: ‘So how many scrolls do you have?’

The Librarian must have bitten on a peppercorn. He went white and choked. Fulvius had to pat him on the back. The disturbance woke Cassius from his nap, so he too was treated to Theon’s look of reproach and thought the food was being blamed. Catching up with the conversation as if he had never been asleep, Cassius muttered under his breath, ‘From what we hear of the famous Library, the freeloading scholars have a stinking lack of morality and all the staff are so disheartened they have almost given up!’ It was the first time I saw my uncle’s partner show his dyspeptic side. That’s dinner parties for you.