London Gateway: Iron Age and Roman salt making in the Thames Estuary. Excavation at Stanford Wharf Nature Reserve, Essex.

Excavation by Oxford Archaeology in 2009 during construction of the Stanford Wharf Nature Reserve, funded and supported by the developer, DP World London Gateway, uncovered remarkable evidence for Iron Age and Roman-period salt making. The excavations shed new and important light on evolving methods of salt production, which undoubtedly reflect wider changes in economy and society in the Thames Estuary between c 400BC and c 400AD. Salt had a particular economic importance in the ancient world as a food preservative; changing scales and methods of production provide an essential background for understanding processes such as urbanisation, civilian trade and military supply. It also had a wide range of dietary, social and symbolic functions, from food flavouring, to an ingredient in medicines and religious rituals. In the words of the Roman naturalist Pliny the Elder, writing in the 1st century AD, 'civilised life cannot proceed without salt'.

In the middle Iron Age, from c 400BC – 100BC the site was dominated by 'red hills', a characteristic feature of ancient salt production on the Essex coast. Following a late Iron Age hiatus, salt making resumed in the early Roman period (c AD 43-120). During this period a piled wooden structure, probably a boathouse, was built facing onto a tidal channel. The 3rd and 4th centuries AD saw the level of salt production intensify to an almost industrial scale. Some salterns of this period were open air while the later ones were inside a variety of buildings. In some respects late Roman production methods were similar to the earlier periods but significant innovations were introduced, including lead evaporation pans and the use of wood charcoal, rather than marshland plants, as fuel. The range of activities diversified to include the on-site production of salted meat and fish sauce, and there are indications of relatively high status domestic life, notably the remains of exotic fruit and seeds.

The specialist finds and environmental reports available to download here support the findings presented in the printed volume, an integrated report which draws on the results of the specialist, scientific and stratigraphic analyses. Overall, the large scale of fieldwork and extensive analysis of the remains have transformed our understanding of the important Iron Age and Roman salt making industry in Essex.

The specialist reports provided in support of the publication, London Gateway: Iron Age and Roman salt making in the Thames Estuary, which is also available for download here, are:

1. Earlier prehistoric pottery by David Mullin and Lisa Brown
2. Iron Age and Roman pottery by Edward Biddulph and Dan Stansbie, with a contribution by Alice Lyons
3. Post-Roman pottery by John Cotter
4. Coins by Paul Booth
5. Metal finds by Ian Scott
6. Slag and high-temperature debris by Lynne Keys
7. Glass by Ian Scott
8. Briquetage and fired clay by Cynthia Poole
9. Ceramic building material by Ruth Shaffrey
10. Worked stone by Ruth Shaffrey
11. Worked flint by Hugo Anderson-Whymark
12. Cremated human bone by Helen Webb
13. Leather by Quita Mould
14. Woodwork by Damian Goodburn
15. Animal bone by Lena Strid
16. Fish remains by Rebecca Nicholson
17. Marine shell by Rebecca Nicholson
18. Insect remains by Enid Allison
19. Plant macrofossils by Kath Hunter
20. Wood charcoal by Denise Druce
21. Diatoms by Nigel Cameron
22. Microfauna by John E Whittaker
23. Pollen by Sylvia M Peglar
24. Soil micromorphology and microchemistry, chemistry and magnetic susceptibility, and FTIR by Richard Macphail, John Crowther and Francesco Berna
25. Stanford Wharf Nature Reserve, London Gateway, Stanford-le-Hope, Essex. Post- excavation assessment. Volume 2: Artefactual, geoarchaeological and palaeoenvironmental appendices edited by Edward Biddulph
26. Radiocarbon and OSL dating: list of dates