By David Willey
BBC Rome correspondent
A new spate of vandal attacks upon some of Rome's best known monuments - including the decapitation and mutilation of several famous statues and monumental fountains - is worrying city authorities.
Vandals are no strangers in Rome. They have been sacking the city, on and off, ever since the fall of the Roman Empire.
But randomly and wantonly chipping off pieces of marble from monuments which have adorned the city for centuries is something new in recent times.
Many anti-war slogans are now stencilled directly on to walls
It began in July, near the Piazza del Popolo. The feet, arms and faces of three marble statues, one of them dating back to ancient Rome, were smashed by unidentified vandals.
They used paving blocks torn up from the road.
The next target was the Fountain of the Bees, at the entrance to the Via Veneto. This was built to the design of the famous Roman 17th Century sculptor Gianlorenzo Bernini.
Last month, a passer-by refreshing himself from one of the water jets flowing into the fountain basin noticed that the head of one of three giant marble bees perched there had been lopped off, and informed the police. No-one was able to say for certain exactly when this had happened.
No arrests have been made in connection with either of these attacks.
Eugenio La Rocca, who is in overall charge of the conservation of Rome's thousands of open-air monuments, has criticised the law relating to vandalism of public property as "too bland".
"No-one ever goes to prison for this sort of crime," he said. "At most they get off by paying a small fine. We need to increase the penalties.
"It's impossible to safeguard all the famous statues scattered throughout the city."
Milton Gendel, an American art historian and connoisseur who made Rome his home half a century ago, has snapped tourists bathing in the fragile and priceless bronze and marble Fountain of the Tortoises, from the window of his apartment overlooking the fountain.
"The classical example of the failure of the authorities to protect the city fabric was the opening to the public of the gardens of former private villas - Villa Borghese, Villa Torlonia, and Villa Pamphilij - which had been filled for centuries with monuments, statuary and antiquities," he said.
"The statues were immediately decapitated and maimed. The police were absent, there was no control. There have been palliative efforts, including a sort of superstitious belief in technology: if you aim cameras at the monuments, it will protect them. Well, it can't."
Roberto di Paola, the architect in charge of Rome's public and private architectural patrimony, believes one way of improving security might be to floodlight the city's most important monuments at night.
"By reflecting light on an object, this enables people to read art in an appropriate way," he told me.
"A restoration is always a stress upon a work of art.
"The actual cost of restoring the damage at the Bernini fountain may not be high, but a damaged work of art always loses value."
Rome has launched an anti-graffiti cleaning squad
Perhaps the most obvious signs of the new vandalism are the spray-painted graffiti which smother the lower part of the walls of practically every building in central Rome.
The city council has hired two permanent squads of cleaners, armed with paintbrushes, solvents and pressure hoses, to go round the city cleaning off the spray paint which defaces both public and private property.
It is a losing battle, according to Cecilia Bernardini, a professional art and stone restorer who accompanies the cleaners on their rounds.
"The authorities tell us to give priority to removing any anti-George W Bush or anti-government slogans or any slander against the police. Many anti-war slogans are now stencilled directly on to walls to try to make them more indelible.
"Rome is not this or that particular building. The whole city is a museum and you have to treat it as such. All the buildings have a context."
The laxity of the police in prosecuting graffiti writers is mocked by the writers themselves.
Papik Rossi, a dedicated Roman skateboarder who counts many writers among his friends, told me: "In Amsterdam it's really hard to do graffiti, there's a special police squad, but in Rome, writers continue to scrawl whatever they want on walls and subways, and scooter riders cross red lights with impunity.
"Graffiti are just one of those easy things to do in Rome...'
Milton Gendel said he found "laughable" the idea that people scribbling on private property are somehow expressing themselves "and therefore may be part of the art world".
"They are vandals. Tolerance is too broad in Rome," he concluded.
That seems to be the nub of the problem. The whole fabric of the city of Rome is fragile.
The choking traffic pollution, the hordes of tourists tramping around, the mostly teenage graffiti writers and the new wave of random vandals are - each in their own way - threatening a unique urban environment, where the history of the past 2,000 years is written in stone all around you.
The eternal city - despite the major clean-up and face-lift it underwent for the Jubilee of 2000 - is suddenly beginning to look very vulnerable.