It is as rare as a Roman inscription, as poor quality as a cheap reproduction, but it is the real thing – "L'Unita', 17 August, 1924" – and the headline is heavy with menace: "The body of Giacomo Matteotti recovered at Riano Flaminio." Matteotti was the leader of the Italian Socialist Party and he was murdered by a man we still regard as a buffoon: good old showbusiness-fascist Benito Mussolini, who even sent Winston Churchill into ecstatics a few years later. Matteotti's death was the critical start of Italian fascism, the beginning of the end of freedom in Italy.

The exhibition of old Communist tracts in the Via Galvani is a dark place. These are the last attempts to cling to the old world, photographs of train strikes, bus strikes, taxi strikes; and then the over-exposed photos of the "Squadrismo", the Blackshirts, the arrests, the torching of buildings.

Looking through these old papers is a chilling experience. We Brits forget what a nasty piece of work "Musso" was and it comes as a shock, as I travel around a Rome I have known so well for so many decades, to find how much of the city was Mussolini's creation. How many times have I stayed in the pseudo-palazzo hotels of the Via della Conciliazione without realising that the whole fandango – so beloved of the network boys and girls as they point their cameras at St Peter's – was the inheritance of fascism, that Musso wreaked destruction on swathes of medieval homes to build these impertinent fake "renaissance" villas.

We love it all now; the long boulevard to the frontier of the holy city, not to mention the great prospect of the Via dei Fori Imperiali up to the Coliseum. Dictators do that kind of thing. Build big. Build to overawe, to oppress, to inflict fear upon the masses; see Tunis-Carthage airport for the Ben Ali version. Mussolini went on to do the same in Tripolitania and Cyrenaica, present-day Libya; let the natives see European civilisational values.

My Dad, I'm afraid, had a soft spot for Musso, especially when Benito crushed the "commies" he hated all his 93 years. When Tariq Ali (born in Lahore 69 years ago) started rabble-rousing in Britain, Bill Fisk raged about him. "Who is this chap, anyway? If he doesn't like it here, why don't they send the damned fool back to where he came from?" And there he was last week, Signor Tariq Ali himself – a long-time hero of mine, wreathed in smiles in Rome, as a certain Signor Roberto Fisk repeated his father's words to an audience of Italian lefties. And naturally, we both found it difficult to disagree about the imperial power of America and the "civilisational" values that we chaps are still trying to teach to those chaps in the Arab world who inconveniently refuse to follow the path to democracy that we recommend to them.

What was really instructive, however, was to wander down the hill to the Capitoline Museum, and slip into another exhibition, this time dedicated to "The Age of Equilibrium" in the 2nd century, when a clutch of intelligent emperors provided, just briefly, power, wealth and peace to the ancient world. Trajan, Hadrian, Antoninus Pius and Marcus Aurelius are all there in massive statuary. There is stern-faced Trajan and a Hadrian who looks eerily like Peter Ustinov. Hadrian returns from the Jewish war in AD 134, cheerfully offering clemency to a bunch of grovelling civilian chaps, leaving behind a wasteland in Palestine for the Jews of these time-honoured lands.

There's a chilling panel of Marcus Aurelius, returning in triumph to Rome, the sculpture of his awful son Commodus hacked off entirely from the original stone. I bet the Romans accomplished this more quickly than the Egyptians, who have been steadily erasing the word "Mubarak" from every hospital and road sign between Alexandria and Aswan.

It's clear that the media bosses of Rome knew their stuff, albeit that stone and marble had to be carved to perform what a few seconds of Sky or CNN can now achieve. Clock up a very impressive victory, and your Roman emperor appears in military costume. Hadrian uttering "mission accomplished" and – to compensate for all those handcuffed Iraqis – a massive statue of a Dacian barbarian/ terrorist, face awed, hands tied behind his back (with rope, not plastic cuffs). As usual, the emperors gave these conquered hordes citizenship of Rome. The Emperor Bush bestowed no US passports on the people of Iraq.

Antoninus, who maintained "good relations with the Senate" – Obama, please note – improved the conditions of his citizens (healthcare, I suppose), decreased taxes – this could be Obama, or even President Romney – and brought "security" to the empire. Most of these men were the adopted sons of emperors; there was no presidential debate.

But there was just one Roman precedent that our present imperial masters have not followed – and thank the Gods for that. If you were a really, really, victorious emperor/president, prime minister in ancient Rome, you appeared in marble, completely naked. You know of whom I thought of for just a few terrible seconds – before I gritted my teeth and fled the Capitoline Hill.