Arriving a day later than the rest of the party, Adrian and I wandered across the Campo dei Fiori, past the last stall selling watermelon and olives, to find my family sitting drinking at a bar on one side of the piazza. They looked as though they were there at sunset every day of their lives.
What had the children been doing on their first day in Rome? Apart from investigating every knick-knack shop in the vicinity (Alex produced a new pair of silver shades, Ben had seen a bag with Pluto on it and Lucy had chosen glittery hair slides), they had also been to the Castel Sant'Angelo - famous in our family as the location of Act 3 of Tosca (in particular the last scene in which Tosca throws herself off the battlements). My father had gone to look for a painting by Barocci in the nearby Chiesa Nuova but had been disgusted to find it dirty, unlit and obscured by a nasty garish 19th-century portrait of a saint. "They don't know what they've got!" he said furiously.
From our long table at the nearby Carbonara restaurant, we had a view of the length of the piazza, its ochre walls deepening in colour as the sky turned from bright blue to inky black. The boys had a playground at their feet: they took a great interest in the scooters parked in rows, and watched, fascinated, as the owner of a motorbike, accompanied by his mother, came out to argue with a helmeted traffic cop. The next time I looked up, Alex had climbed on to the lip of the fountain where he stood, dramatically backlit, like a statue.
The waiter was unfazed by the demands of the largely absent children (half portions of spaghetti, no sauce) and the rest of us (brains, fried zucchini flowers and saltimbocca, washed down with great gulping draughts of cold, light Pino Grigio), and got into the spirit of the occasion, addressing my father as "Eccellenza".
When the children went to bed, my sister asked the hotel night porter to keep an ear out for them. We found a bar table near the flower stall, buckets of sunflowers still beaming after midnight, and ordered grappa. It gave me a headache so instantly I might as well have hit my head on the table.
The next morning we re-assembled, red-eyed and crazed with lack of sleep, for an excursion to the Galleria Borghese, set in a wooded park that covers a vast chunk of central Rome with pine avenues, lakes and elaborate gardens. The gallery had been closed for restoration for years, so none of us had seen it on previous visits.
As I walked in, Adrian was already busy pointing out the soft look of the marble cushion on which the half-naked figure of Pauline Bonaparte Borghese reclines. Ben took my hand. "Does she have a bottom?" he inquired. "Well, let's have a look." We walked solemnly around to Pauline's backside, where we duly admired the dimples and cleft of her bottom. My father walked by. "What on earth's the point of Canova when you've got Bernini next door?" We came upon him later, ecstatic at discovering a Correggio he hadn't expected to see; with a flourish, he showed me the Danae, roused by Apollo's messenger while two putti busy themselves with a game of tick-tack-toe.
Eventually, we all staggered out into the sunlight, towards the Pincio and a marvellous restaurant, the Casina Valadier, where my parents had shared a romantic lunch in 1960. When we came upon the restaurant, a tall villa in faded reds with a superb view from its first-floor terrace, the mildewed tables piled up outside showed it had been closed for some time. So instead, we bought lukewarm, dry pizza and cans of beer from a Bangladeshi vendor and sat among the pigeons, looking alternately at the shuttered windows and across the terracotta roofs and marble domes of the city.
Adrian was keen to see the Colosseum, having read perhaps an unhealthy amount on the nature and cruelty of the spectacles staged there in the dying throes of the Roman Empire. My mother declared she couldn't bear to go ("All those Christians..."). Instead I went with her to find Keats's (rather cramped) house at the foot of the Spanish steps and then down the via Condotti: fashion central.
We found ourselves at the doorstep of Prada, egging each other on. On the top floor, we fell into the hands of two softly vampiric saleswomen which is, I suppose, how we came to be gaping at ourselves, she in a bulbous jacket and skirt, I in an orange dress that was several sizes too big.
We caught up with the rest of the family at the entrance to the Domus Aurea, a wing of Nero's palace which had, just two days previously, been opened to the public after years of excavation. As we dragged them through the chilly subterranean hallways, the children begged us to fill in the void with tales of what each room might have looked like in AD64. Sadly, the guide - with typical Roman indifference - knew nothing at all about the palace and its history.
Later, over carciofi alla giudecca at the Piperno, a delightful restaurant tucked in a corner of the Roman Ghetto, my mother suggested a contest. Who could describe the fall of the Roman empire in the fewest number of words? "Spread themselves too thin." "Plumbing." "Bad water and sex."
The following morning we followed my mother to St Peter's, where I was debarred from the cathedral, having forgotten to cover my shoulders. The others emerged triumphantly. The children, who were rather subdued and impressed, had been amazed by St Peter's foot, flattened by centuries of devout kisses. We showed off our souvenirs: 3-D postcards of the Assumption of the Virgin (complete with moving cherubs), and The Last Supper, in which the artist's skills at perspective had been boosted with the aid of multi-layered plastics.
As we squinted at the host of Bernini's saints on top of the great colonnade that encircles the piazza, my mother waved towards a palace behind the Vatican walls. "That's where Giorgio lived," she said. Giorgio, the Pope's nephew, had been infatuated with my mother on one of her early visits to Italy and used to send her flowers plucked from a mountainside or ravine, pressed between the pages of Petrarch or Dante. He was eventually whisked off his feet by a Belgian who landed her helicopter on the Vatican lawns.
A brass band struck up at one end of the colonnade, and we walked idly towards its Sunday-best tones. In the distance, we saw a saint on its dais being carried out at the front of a procession. As we watched the precarious arrangement of flying angels about a standing saint, the angel's feet wobbled. Then as we stared in disbelief, one small foot rubbed against the other. We had happened upon the annual parade of human figures that are arranged to illustrate the mysteries of the saints. After an hour under the midday sun, Abraham's angel was looking distinctly seasick.
We repaired to Trastevere, Rome's Left Bank, for lunch in the piazza Santa Maria, the heat refracting the noise of eating and talking. Leaving in a well-fed stupor, we wandered our separate ways; Adrian and I taking a long route that took us through the cobbled backstreets, silent and shuttered against the heat in an almost rural torpor, just two streets back from the busy highway that runs along the Tiber.
In the late-afternoon, we gathered on the hotel roof terrace, hot and sleepy, to look out over the domes and roof gardens to the hills beyond. "I need to go shopping," said Lucy.
YOU CAN fly to Fiumicino (Rome's main airport) from Heathrow on Alitalia (0171-602 7111), British Airways (0345 222111) and Ethiopian Airlines (0171-499 9119). Alitalia and BA also fly from Gatwick, and Debonair (0541 500 300) flies from Luton.
Go (0845 60 54321) flies from Stansted to Rome's second airport, Ciampino. Charters to Ciampino are available through agents such as Italy Sky Shuttle (0181-748 1333).
From Fiumcino there is a fast rail link to Termini station, though the stopping service is both cheaper and possibly more convenient for most tourist areas. Rome's second airport is closer to the city, with a bus/metro link to the city.
More information: Italian State Tourist Office, 1 Princes St, London W1R 8AY (0171-408 1254; brochure request line 0891 600280).