The foundations of complete Roman town houses found under the city centre park are thought to be some of the most remarkable Roman finds yet.
And experts believe the only reason they survived was because they were located under a park which has remained green space since the Roman period.
Archaeologists were surprised to uncover three almost complete Roman buildings, footings of which have survived more than 1,600 years in the centre of a thriving city.
The scans appear to show two large masonry houses, which would now be the equivalent to Chichester's grand Pallant House Gallery building, and would have been owned by someone of great importance. The third building is of great interest because of its unusual shape.
The discovery follows a request by local geophysics specialist, David Staveley to use ground penetrating radar equipment to look for remains. Chichester District Council's archaeologist, James Kenny, gave permission to scan the parks, thinking they were the most likely place to discover remains that will have survived.
Following the results from the scans, Kenny and the local archaeology society carried out a very small dig in the park.
He said: "What's remarkable about this discovery is that it has survived over 1,000 years in a currently occupied city. The only reason they have survived is because they are under a park that has never been built on.
"It's almost unique to see Roman houses survive in this type of setting and to be so complete.
"The location marks what may have been one of the more affluent parts of the Roman Town, with these houses being the equivalent to a property worth millions of pounds in today's society. The two houses have walls surrounding complete rooms, which are set around a courtyard or atrium. There is also a deep masonry building with a rounded end. We are intrigued to find out what this building is. It could be a cellar, part of a bath house, or something even more exciting. We can't wait to find out.
"These are definitely going to be some of the best surviving Roman remains that have been uncovered in a city environment."
James believes that the houses were originally located on a street, but that this hasn't survived because of the World War Two reservoir that was built in the park. The scans reveal that another Roman street ran further east under Priory Park, but this will not be uncovered.
"We are just going to focus our attention on the area south of The Guildhall building that is located in the park. We're very lucky, because this is an area that is not used for any specific purpose and so we should be able to carry out a dig to uncover the buildings that we have found. This is sure to unlock even more buried secrets and items of importance."
Chichester District Council is now looking for funding to pay for a series of excavations in the coming years and will put a case to the Heritage Lottery Fund among others.
Once underway, the authority plans site tours and information on the dig progress and eventually, to return the site to its main function as a park once information has been gathered and 3D images created.
Priory Park is located in the centre of Chichester and was given to the people of the city by the Duke of Richmond as a First World War memorial. 2018 will mark the centenary of the both the park and the end of the war, with plans underway to arrange events in the park to tie in with this.