The Regni (also the Regini or the Regnenses) were a Celtic tribe, or group of tribes, living in Britain prior to the Roman Conquest, and later a civitas or canton of Roman Britain. They lived in what is now Sussex, as well as small parts of Hampshire, Surrey and Kent, with their tribal heartland at Noviomagus Reginorum (modern Chichester).

Territory It is generally accepted that the Regni broadly occupied the region that later became Sussex. Surrey is sometimes included within Regni territory and sometimes within the territory of the Atrebates to the north. However the archeological record north of the Weald shows significant differences to the south and so it would appear Surrey was not normally included in the Regni tribal area.'The Roman Period - South East Research Framework Resource Assessment', 2013, with additions in 2018 and 2019, Martyn Allen, David Bird and Ben Croxford

The tribe was surrounded on the west by the Belgae, on the north by the Atrebates, and on the east by the Cantiaci. To the south and east across the Oceanus Britannicus or Oceanus Gallicus (the present day English Channel) lay Gaul and the tribal areas of the Caletes, Veliocasses, Catuslugi, Ambiani and the Morini.

Name The tribe’s existence is traced to the city of Chichester. During the Roman era, Chichester was a Civitas Capital, indicating it was a minor capital city governing a small tribal region. While maps typically indicate the Atrebates as the tribe occupying Chichester, the name of the city suggests the Regini actually controlled the area.Russell, M., 2010. Bloodline. Gloucestershire: Amberley Publishing Ltd.

Chichester's Roman name, Noviomagus Reginorum, is widely accepted to translate as “New Market,” but the meaning of Reginorum has been a subject of debate. Originally interpreted as “The People of the Kingdom,” i.e., the people of Cogidubnus’ client kingdom, a comparison with other civitas capitals reveals a different meaning. For instance, the tribal capital of the Durotriges tribe in Dorset (Dorchester) is Durotrigium, corresponding to the land of the Durotriges. This naming convention is also seen in other regional capitals like Atrebatum (Silchester) within Atrebates territory and Belgarum (Winchester) in Belgae territory. Applying this pattern to Chichester suggests that Reginorum should be understood as “New Market, Land of the Regini”.Manley, J., ed. 2008. The Archaeology of Fishbourne and Chichester A Framework for its Future. Lewis: The Sussex Archaeology Society.Russell, M., 2006. Roman Sussex. Gloucestershire: Tempus Publishing Ltd. Regnini or Regni is believed to come from a Brythonic word Regini (and the Gaulish and Old Welsh word Regin) meaning the “proud ones” or the “stiff ones.”

The name of this people is not entirely certain. Ptolemy refers to the (), whose only city was , Noiomagus.Ptolemy, ii. 3. § 28. This appears to be the same place as Navimago RegentiumRavenna Cosmography. or Noviomagus Regionorum, from which Regnenses, occurring in some modern sources,"Noviomagus Regnensium", in The Princeton Encyclopedia of Classical Sites, Richard Stillwell, William Lloyd MacDonald, Marian Holland McAllister, eds., Princeton University Press (1976). appears to be derived. The location is generally supposed to be Chichester. The Antonine Itinerary refers to a place called Regno at the end of Roman Road 7, perhaps referring to a site along the coast of the Solent. Some scholars reject Regnenses in favour of Ptolemy's Regni or a Brythonic name Regini.Kenneth H. Jackson, "Roman–British Names in the Antonine Itinerary", in Britannia, vol. I, pp. 68–82 (1970): "Even the reading of the genitive plural tribe name in Regnentium is a tendentious emendation…. To go further and turn all this into Regnenses, 'The People of the Kingdom', is more than rash…. The tribal name in Ptolemy is Regnoi, Rignoi, or Reginoi…. It is proposed…that this was British Regini". This opinion concurred with by Graham Webster, The Roman Invasion of Britain, p. 188, Routledge (2003): "This… is the more acceptable", citing Barry Cunliffe, "The Regni", from Peoples of Roman Britain, Duckworth (1973) for the similar Gaulish and Old Welsh regin, and hypothesizing Regini, meaning "proud, stiff, upright".

Background By the Middle Iron Age (c. 250 BC) the first millennium BC hillforts on the northern and southern edges of the South Downs, such as Chanctonbury Ring and Highdown Hill had fallen out of use, replaced by new, smaller number of more dramatic hillforts on the Downs, such as at the Caburn, Cissbury and the Trundle. Unlike in the region of Wessex to the west, settlement close to these hillforts was limited. These hillforts were probably built to be impressive monuments rather than defensive structures, uniting local communities and giving them a renewed sense of identity. Also at this time, the coastal plain to the west of modern-day Brighton was resettled. By the end of the Middle Iron Age (c. 100BC) the downland hillforts had been abandoned, and settlements on the coastal plain became more numerous.

Late Iron Age (c. 100 BC – early 1st century) The Regni were probably a group of native tribes influenced by the Belgae. The sudden appearance of new coin designs hints that some tribes in south-eastern Britain might have been under the control of a Belgic elite and adopted aspects of their culture as early as 100–80 BC. The distribution of Aylesford-Swarling pottery in south-eastern Britain has also been associated with the Belgae; however, recent studies proposed that migration might not have played as significant a role as once thought, with increased trade connections being more important, although this remains uncertain.Bean, Simon C (1994). The coinage of Atrebates and Regni (PDF) (Ph.D.). University of NottinghamArchaeologia 52, 1891Sir Barrington Windsor Cunliffe, CBE, FBA, FSA (born 10 December 1939), known as Barry Cunliffe, is a British archaeologist and academic

The Regni entered a period of historical documentation around 75 BC, with the emergence of written records and the rise of a literate society, accompanied by a more complex economic system. Various groups' movements were no longer tracked solely through pottery artefacts but also through the identification of coins, marking a level of literacy, the aggregation of core cultures in specific regions, and the introduction of monetary transactions for trading surplus goods. Driven by pressures from tribal factions on the Continent and the Romans' continued conquests in Gaul, rebellious groups set out across the sea in search of unoccupied lands, especially where local chieftains resisted Roman rule. This likely marked the initial 'invasion' of Sussex, although detailed accounts of battles and conquests are scarce. The Gallo-Belgic tribes, also known as Celts, integrated their dominance into the existing social structure rather than replacing it; even during the later Roman era, indigenous Neolithic inhabitants coexisted with Iron Age urban residents in Sussex. Significant newcomers like Commius of the Atrebates, who sought sanctuary in Britain around 52 BC, brought and promoted a level of civilisation influenced by Rome. The Atrebates settled across a wide area encompassing Hampshire, Wiltshire, and parts of eastern Sussex, with some falling under the rule of the Catuvellauni by 25 BC.Wilcuma English Heritage A History of Sussex HUNTERS, WARRIORS AND THE ROMAN PEACE (https://www.wilcuma.org.uk/sussex/a-history-of-sussex)

Following the initial 'conquest' and subsequent power shifts, Sussex stabilised into a new order. The influence of the Atrebates extended toward the Ouse and partially into the Weald, while tribes in the northeast and Kent maintained a more defensive stance, with Mount Caburn being a strongly fortified boundary town. The new ruling class notably abandoned the large developed hill-forts at the Trundle and Cissbury in favour of sophisticated urban centres on the coastal plain. This was particularly in the Selsey-Chichester area, which has since succumbed to coastal erosion.Beach Sustainability and Biodiversity on Eastern Channel Coasts Interim Report of the Beaches At Risk (BAR) Project January 2005

The settlements of the Regni tribe are mapped out in the West Sussex region, particularly situated around the River Lavant and between the river systems of the Arun and Adur. Noteworthy is the Major Oppidum (City) located in Chichester, along with the Selsey/Mixon rocks. It's believed that the Cymenshore/Mixon rocks were submerged around the 7th or 8th century AD, Large iron age shrine/votive site, also of significance is the Romano-Belgic Palace found at Fishbourne, which included a coin mint and shrine at Ratham, alongside ironworks at Boxgrove. The discovery of the Mystery Atrebate Warrior and the burial of the North Bersted Man at Bersted contribute to the historical narrative or the Regini.

Trade and fishing activities were prevalent at a small enclosure in Pagham, while Climping was recognised as a major trade centre. Coldharbour at the mouth of the Arun yielded a Roman hoard along with gold and silver Celtic coins. The Romano-Belgic Villa at Bognor and another trade centre at Tortington also produced gold and silver Celtic numismatics. Arundel served as a large Iron Age population centre, with substantial enclosures at Rewell Wood nearby, which during the late Bronze Age, was one of the largest settlements in Europe. There was a Romano-Belgic Villa at Bignor, and at Coldharbour, south of Stoke, a small quantity of silver Celtic coins was found.

Various settlement enclosures at Warningcamp may be linked to the Rewell Wood tribes, while the Burpham vicinity yielded Iron Age artefacts along with bone fragments from burials and signs of earthworks. The trade inlet at Nutbourne and Bosham, located at Chichester Harbour, also produced gold and silver Celtic coins. Wittering, which is now submerged, served as another trade centre at Chichester Harbour inlet, while Tournerbury hill fort is positioned approximately 100 metres from the Solent shoreline on nearby Hayling Island, just over the modern border with Hampshire, where Iron Age and Roman pottery have been discovered.

Rowlands Castle has shown evidence of Romano-British pottery, bricks, and tiles, benefiting from the nearby availability of suitable clay. Goosehill Camp features multiple enclosure hillforts situated on sloping grounds just below the ridge summit of the Sussex Downs. The Apple Down/Kingley Vale Ancient Forest is known as one of the oldest forests in Europe, containing yew trees that are up to 2,000 years old—some of the oldest living organisms in Great Britain.

The Trundle hillfort is found on the notable St. Roche's Hill, recognised as one of the prominent hills along the southern edge of the Sussex Downs. In Chilgrove, Bronze Age and Roman earthworks, cross dykes, and an ancient field system were established. Funtington features Coldharbour trade activities along the River Lavant, along with earthworks, cross dykes, a camp, and a field system, while a small quantity of gold and silver Celtic coins was discovered. Keynor was identified as an inland trade point that has since become silted.