Stane Street is the modern name given to an important 90-kilometre-long (56 mi) Roman road in England that linked London to the Roman town of Noviomagus Reginorum, or Regnentium, later renamed Chichester by the Saxons. The exact date of construction is uncertain; however on the basis of archaeological artefacts discovered along the road, it was in use by 70 AD and may have been constructed in the first decade of the Roman occupation of Britain (as early as 43-53 AD).
Stane Street shows clearly the engineering principles that the Romans used when building roads. A straight line alignment from London Bridge to Chichester would have required steep crossings of the North Downs, Greensand Ridge and South Downs and so the road was designed to exploit a natural gap in the North Downs cut by the River Mole and to pass to the east of the high ground of Leith Hill before following flatter land in the River Arun valley to Pulborough. The direct survey line was followed only for the northernmost 12.5 km (8 mi) from London to Ewell. At no point does the road lie more than six miles from the direct line from London Bridge to Chichester.
Today the Roman road is easily traceable on modern maps. Much of the route is followed by the A3, A24, A29 and A285, although most of the course through the modern county of Surrey has either been completely abandoned or is followed only by bridlepaths. Earthworks associated with the road are visible in many places where the course is not overlain by modern roads and the well-preserved section from Mickleham Downs to Thirty Acres Barn, Ashtead is listed as a scheduled monument.
Stane is simply an old spelling of "stone" (Old Norse: steinn) which was commonly used to differentiate paved Roman roads from muddy native trackways. The name of the road is first recorded as Stanstret in both the 1270 Feet of Fines and the 1279 Assizes Rolls of Ockley. It is also referred to by the modern spelling as Stone Street as far back as medieval sources. There is no surviving record of the road's original Roman name.
A number of first-century pottery fragments and coins have been found along the road, including Samian ware of Claudian date at Pulborough. The earliest coins found are of Claudius (41–54 AD), with others of Nero, Vespasian, Titus, Domitian and Nerva (96-98 AD). This is consistent with the road being in use by 60 to 70 AD, possibly earlier. 
Surveying and construction
The direct line from London Bridge to Chichester passes over the North Downs at Ranmore (200 m above Ordnance Datum), the Greensand Ridge at Holmbury St Mary (260 m OD) and over the South Downs near Goodwood Racecourse (167 m OD). The steep gradients which would have been required if the road had followed a direct line would not have been practical for wheeled traffic and so the Roman engineers designed the road to cross the North Downs by natural breach cut by the River Mole and to pass to the east of the high ground of Leith Hill. The geology of the region was also considered and the road leaves the direct line at Ewell to move onto the well-drained chalk of the North Downs, in preference to remaining on the London Clay. The road is able to make a more gentle ascent of the South Downs escarpment at Bignor than was possible at Goodwood and the chosen route avoids the need for the road to cross the steep sided River Lavant valley at East Dean.
In order to accommodate and exploit the complex topology of the region, the road used four main straight sections (sometimes referred to as limbs) connected by shorter linking sections. Each limb could be surveyed separately using local vantage points. The major limbs were:
- London Bridge to Ewell
- Ewell to Mickleham Downs
- South Holmwood to North Heath near Pulborough
- Pulborough to Chichester
The Roman surveying technique is clearly demonstrated by the longest of the four limbs from South Holmwood to North Heath (24.5 km or 15 miles). The line that the road follows runs between two prominent hill tops, Borough Hill on the South Downs and Brockham Warren on the North Downs. There are some short local variations from the straight line of the limb, for example the Roman road loops to the west for around 200 m at Okewood Hill to cross a small stream at a convenient fording point. South of North Heath the road turns by an angle of 7 degrees to head towards the crossing of the River Arun at Pulborough. North of South Holmwood, the road turns by a further 7 degrees to the north to approach Dorking.
The average width of the paved road is 7.4 metres (24 ft), or 25 Roman pedes. This is wider than the average 6.51 metres (21.4 ft) or 22 pedes for Roman roads in Britain. The overall width between the outer ditches, which can still be seen on aerial photographs taken over the South Downs, is 25.6 metres (84 ft) or 86 pedes. The actual width of metalling varies from place to place, and the outer ditches were found to be 27.4 metres (90 ft) apart at Westhampnet. Sections of intact road that have been excavated in several places show a variety of local materials, with the agger often being constructed of alternating layers of sand and gravel paved with large flint nodules, or sandstone, surfaced with smaller flint or sand and gravel. The metalling was generally about 30 centimetres (0.98 ft) thick at the centre with a pronounced camber. Near to the Alfoldean station the metalling was constructed from iron slag in a solid 30 cm thick mass.
There are two known posting stations or mansiones along Stane Street, where official messengers could change horses and travellers could rest. These are at Alfoldean and Hardham. Mansiones were normally rectangular fortified sites of about 1 hectare (2.5 acres). The station at Alfoldean has been excavated. The Alfoldean site is just south of the River Arun and partly covered by the A29 road. It was excavated by the Channel 4 archaeological television programme Time Team, revealing the remains of a two-storey mansio built around a courtyard and also many other buildings. The site was enclosed by massive ramparts and ditches four metres wide and as deep which were dated by pottery finds to around 90 AD. The ditches were filled in by the mid-third century. The team's view was that the site had been an administrative and taxation centre for the Wealden iron industry. The western side of the Hardham station was destroyed by construction of the Pulborough to Midhurst railway, but most of it, including the north and south gateways, remains.
Two further stations at Merton Priory and Dorking have been postulated as being at suitable intervals, though the sites would now be hidden under modern development. Alternative sites for the posting stations have also been suggested at Ewell and Burford Bridge (where the road crossed the River Mole).
London Bridge to Ewell
The line of the road runs south west from London Bridge, between Borough High Street and Elephant and Castle forming the course of the present-day Newington Causeway, then through Clapham and Tooting down to Colliers Wood and Merton. Clapham Road and Kennington Park Road lie on top of Stane Street. It then crosses the River Wandle at the site of what later became Merton Priory, and is then closely followed by the A24 from Morden to Ewell. This is the only section of the road that is on the true line from London Bridge to the east gate of Chichester. The road passes through Sutton Common and forms the northern boundary of Sutton, formed from Old English 'sūth' and 'tūn', meaning "the south enclosure", which may have derived its name from its southerly position in relation to the road; the enclosure could have been Oldfields Farm, located at what is now Rosehill.
Ewell to South Holmwood
At Ewell it bears to the left slightly, avoiding wet difficult alluvial soils by moving onto the chalk, to cross the North Downs near Langley Vale. The section from Thirty Acres Barn, Ashtead to Mickleham Downs is well preserved and is listed as a scheduled monument. Stane Street crossed the River Mole via a ford close to the site of the modern Burford Bridge and excavations carried out in 1937 at the site revealed a "flint-surfaced approach to [a] ford at low level having all the signs of Roman workmanship". The road passed through Dorking which was almost certainly a Roman station, although the exact course through the town is uncertain. This route takes the road east of Leith Hill, one of the highest hills in southern England at 294 metres (965 feet).
South Holmwood to Pulborough
South of Dorking, near South Holmwood, Stane Street takes a line sighted from London Bridge to Pulborough with most of this section still in use as the modern A29 which follows the line very closely through Billingshurst as far as Pulborough. This line to the east of the middle reaches of the River Arun is mostly free of steep gradients, although the modern road does avoid the hill at Rowhook. Just to the south of the steep descent from Rowhook through Roman Woods, where the road bridged the River Arun, some of the timber piles on which the bridge was built are still present in the river bed. Scattered Roman tiles and squared stone in the river bed show that stone bridge piers were built above the piling. The Alfoldean station is some 30 metres (33 yd) south of the bridge site.
Pulborough to Chichester
At Hardham, south west of Pulborough, there was a junction with the Greensand Way Roman road to Lewes and a posting station near the junction. From here the alignment makes a beeline for Chichester, and passes the notable Roman villa at Bignor, before making a slight detour from the line where it climbs the escarpment of the South Downs, climbing a spur of chalk at Bignortail Wood and continuing as a man made terrace across the steep hillside. This terrace is well preserved on the downhill side of the top of the modern track which leads to the hilltop car park at Bignor Hill.
Up on the open heath of the downs the line of the road can be followed very well on foot and is free of modern roads and paths. Walking south from Bignor Hill one soon comes to open sheep-grazed pasture at Gumber farm where the scale of the agger of the road can be clearly seen. The spire of Chichester cathedral can be seen above the distant trees, slightly to the right of the road line as the road heads for Chichester's east gate. Further on at Eartham Woods where the Monarch's Way long-distance path follows the route, the flint surface of the well-preserved road is exposed, the trees are mostly cut back to the boundary ditches, and the road seems little different from the time when the Legions left Britain. Although the Saxons made Chichester the capital of the South Saxon kingdom only the southern 7 km (4.3 mi) of the southern section of the road into the western Weald have remained in use, as the A285.
At Westhampnett, near the Rolls-Royce works, the Roman coastal road, which became the older A27 road, branches from Stane Street at the mini-roundabout. The Roman road continues via Broadwater, Sompting, Lancing (along a road still named The Street) and part of the Old Shoreham Road (the A270) through to Novus Portus (around modern Portslade).
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