Back we go this week to the bloody Romans (Timewatch, BBC2 xxx). I often wonder at how bloodthirsty people are, and seem always to have been. On television every night are programmes based largely on blood, from hospital dramas to old-fashioned police thrillers. Films and electronic games, even kids’ cartoons, always seem to revolve around violence.

We talk piously about wanting to end genocide and torture, and yet for centuries human beings have enjoyed watching other people suffer. In the days before television or cinema, the greatest crowd-pullers were public executions. At Tyburn Tree in London – near today’s Marble Arch – 60,000 people were hanged, often in batches, and huge stands were built to accommodate the crowds who came to watch. And when mere hanging was too good for them, the victims might be castrated, drawn, and quartered as well.

Around AD 100, when the mighty Roman republic had given way to what were effectively dictatorships under the Caesars, the satirical writer Juvenal wrote ‘the people who once bestowed commands, consulships, legions, and all else, now meddle no more and long eagerly for only two things — panem et circenses  - bread and circuses.’ In other words, instead of waging wars to make their empire stronger, or even being concerned about politics, the Roman citizens just sat back on their sofas, guzzled pizza, and watched the bloody games – they were the first sadistic couch potatoes.

Circuses were nothing to do with clowns or trapeze artists. Circus meant a racetrack – think Ben Hur. But when the people got bored with the races the organizers invented new spectacles – especially fights to the death involving gladiators, pitted against one another or against wild animals – bears and lions, imported from distant lands.

Once these bloodthirsty spectacles were established in Rome, the idea spread rapidly throughout the empire, and amphitheatres were built even in cold Britain, the most northerly outpost. There was one in London, beside what is now the Guildhall; one at Caerleon in South Wales, and others at Cirencester, Chichester, Dorchester, Silchester, and Chester – my dad told me I could tell these were Roman camps, since the Latin for camps was castra.  None of these looks like a racetrack; rather an open space for bloody combat.  After each bout, slaves would sprinkle sand over the gore, and because the Latin word for sand was arena the space came to be called the arena.