Under Another Sky, by Charlotte Higgins, review The impression that Roman Britain was a second-rate province is wrong. The basilica that held Londinium's law courts and senate was the biggest Roman structure north of the Alps. Claudius's capture of Camulodunum, modern Colchester, was so popular that the Roman Senate granted him permission to celebrate a triumph - the ritual procession through Rome only undertaken after a great military victory. The emperor was given the honorary title Britannicus. The emperor's victory also inspired the first known appearance of Britannia: in a sculpture at Aphrodisias, a Roman city in Turkey, Britannia is depicted in a tattered dress, pinioned to the ground by Claudius, his fist poised ready to batter her. Roman penetration was deep right across the country: mosaics have been found from Brading on the Isle of Wight to Castlecary in Scotland. The Romans got even further north - there's a line of signal stations north of Dundee along the Gask Ridge; Tacitus says the whole island was conquered. Higgins tracks down chunks of Roman masonry in the oddest places: in a field near Brecon; in a City of London underground car park, where she finds a section of Roman wall flanked by motorbikes. At one point, the camper van runs out of steam as it climbs the Lake District fells in search of Hardknott Castle, a Roman fort perched high on a wind-blasted crag. Still, we must be careful before we start calling Roman sites like Silchester, near Basingstoke, "the Pompeii of Hampshire," as the Victorians dubbed it. I don't imagine many Neapolitans call Pompeii the Silchester of Campania. But it's undeniable that the Roman presence here was significant, as are its echoes in the modern British psyche. It would be strange if the Romans didn't have some hold on us today. They were here for a long time - the equivalent of the interval between Shakespeare's lifetime and our own. And the Romans were here at the moment when Christianity arrived. The first known British use of the word "Christian" comes in a lead tablet found in Bath, appealing to the goddess of the spring for the return of stolen silver coins from the thief, "whether pagan or Christian." Our modern outlook is by no means entirely Roman; but we would be extremely different if they'd never come, seen and conquered. Harry Mount is the author of Amo, Amas, Amat and All That (Short Books) Under Another Sky by Charlotte Higgins 288p, Jonathan Cape, £18 (PLUS £1.35 p&p) 0844 871 1515 RRP £20, ebook £11.88