With the Romans and Celts at Farley

High on windswept Farley Heath, you're standing close to the remains of a Romano-Celtic temple, one of the few Roman sites to have been found in Surrey. In Roman times, you'd have got here along the branch road that led north west from Stane Street - the busy London to Chichester highway - at present day Rowhook, on the outskirts of Horsham. You'll cross the line of the road near Winterfold Cottage, and again on Ride Lane, just after the junction with Madgehole Lane.

The Romans had a plethora of religious beliefs. They venerated Rome and the Emperor, as well as Jupiter and other Graeco-Roman gods; in far flung outposts like Britain they also embraced the local and pagan religions. By the 3rd and 4th centuries Christianity was gaining ground, and there was increasing interest in mystical religions like the cult of Mithras, the ancient Persian light god.

Both Roman and native gods were worshipped together in Britain, and distinctive Romano-Celtic temples were evolved to accommodate the various different religions. These designs consisted of a square or rectangular tower surrounded by a lean-to verandah, and they were quite unlike other buildings in the Roman landscape.

Farley was typical, and you can see the outline of its foundations just a few paces north of the car park at the start of your walk. The two concentric masonry squares are a modern reconstruction, built to show the ground plan that was discovered by Martin Tupper in 1848, and confirmed by subsequent excavations in 1939 and 1995. The temple itself was built before the end of the 1st century ad. It was enclosed within a precinct wall, or temenos, which was also located during the excavations but has since been re-buried. Tupper's finds, which included several decorated bronze strips from a priest's sceptre, are now in the British Museum.

The temple was fairly isolated, although there was a Roman villa just south of Pitch Hill, some 3 miles (5km) back down the road towards Stane Street. No other permanent buildings have been found inside the temple precincts, but the site would have been the focus of regular religious rites, and possibly occasional markets or fairs as well. The temple remained in use until the end of the Roman occupation early in the 5th century, and it seems that the building burnt down some time before the year 450.

Where to eat and drink

You won't find any refreshment stops on this route, so I'd recommend that you pack a drink and a chocolate bar at the very least. After your walk, follow the road towards Shere. Just beyond the railway bridge you'll come to the pink-washed William IV at Little London, a 16th-century free house with flagstone floors and a huge inglenook fireplace. They serve good home cooked food (though not on Sunday evenings) together with a decent range of real ales.

While you're there

After seeing the temple, you might be curious to know what a Roman priest's headdress looked like. Well, you can see one in Guildford museum. Right next to the Castle Arch in Quarry Street, you'll find Surrey's largest collection of archaeology and local history; everything from Palaeolithic hand axes to a super collection of 17th-century pottery and glass. The needlework displays include samplers, patchwork and baby clothes, and the museum also features pictures and artefacts illustrating most aspects of local life. The museum is open Monday to Saturday, and admission is free.

What to look for

I saw dozens of rooks foraging in the fields as I tramped down Ride Lane towards Farley Green. Rooks return to established breeding sites year after year, building their large, sprawling nests in tall trees such as beech or oak. It's not unusual to find 50 or more nests in a single rookery. There's an old saying that, if you see two crows, then they're actually rooks. The crow always seems to be a much more solitary bird than the noisy, gregarious rook. If you want to be certain of telling these large black birds apart, then look for the rook's conspicuous bare cheeks at the base of the bill.