In the following years, additional remains such as pottery fragments and portions of mosaic tiles were unearthed by local inhabitants who lived within close proximity to the site.

[4] This rediscovery of the ancient structure caught the attention of the Sussex Archeological Society and triggered the first series of excavations, directed by the archeologist Barry Cunliffe and his team in 1961.

[4] To the surprise of archeologists and historians alike, each stage of excavations revealed previously unknown details surrounding the site's vast and complex history.

[4] For instance, from 1995 to 1999, the archeologists John Manley and David Rudkin conducted digs that focused on southern portions of the site, which exposed significant evidence of human activity prior to the Roman conquest in 43 AD.

[6]  Over the course of five years, Manley's team of archeologists discovered nearly twelve thousand artifacts, including flint tools that are believed to date back to the Mesolithic period (around 5000–4000 BC) and could indicate the presence of a hunter and gatherer settlement near the present-day location of the Fishbourne palace.

[6] However, the most intriguing and significant evidence of pre-Roman human activity at the site comes from a ditch containing nearly seven hundred fragments of pottery and a cup that can be traced back to a period within the Late Iron Age.

[6] The findings made by Manley and his team challenge Cunliffe's earlier assumptions by suggesting the likely presence of significant human activity at Fishbourne prior to 43 AD.

The life-size head of a young man carved in marble, found during excavations in May 1964, and identified as a likeness of Nero aged 13 created at, or shortly after, his formal adoption by the emperor Claudius in 50 AD[10] probably originated from the proto-palace.

The full-size palace with four residential wings surrounding a formal courtyard garden of 250 by 320 feet (75 by 100 metres) was built in around 75–80 AD and took around five years to complete, incorporating the proto-palace in its south-east corner.

The decoration of the palace was elaborate, including wall paintings, stucco mouldings and opus sectile, marble polychrome panels, examples of which are in the museum.

In the middle of the second century AD, further major redesign included demolition of the recent baths suite and the eastern end of the north wing, probably due to subsidence from underlying earlier infill.

The accepted theory, first proposed by Barry Cunliffe, is that the early phase of the palace was the residence of Tiberius Claudius Cogidubnus (or Togidubnus), a pro-Roman local chieftain who was installed as king of a number of territories following the first stage of the conquest.

Cunliffe correlates this event with the construction of a large masonry extension of the palace in 70 AD, which was fitting for an individual of such a high status in order to support his theory.

[14] Two inscriptions recording the presence of Lucullus have been found in Chichester and the re-dating, by Miles Russell, of the palace to the early 90s AD, would fit far more securely with such an interpretation.

[15] Additional theories suggest that owner of the palace was either Verica, a British client king of the Roman Empire in the years preceding the Claudian invasion, or even one Tiberius Claudius Catuarus, whose gold signet ring was discovered nearby in 1995.

[4] Over the course of the following years, the local inhabitants of Chichester raided the site for its building stones, which is why the ground-stone foundations of the walls are the only part of the ancient structure remaining today.

The Sussex Archaeological Society lost an estimated £1 million in income from visitors, and in June began a fundraising appeal so that it could continue maintaining Fishbourne Roman Palace along with other properties.