Groundworks took around three times longer than expected due to the unprecedented nature range of objects and material dating back to the 10th century.
The findings are expected to be become a major selling point of a stay in Sir Richard’s first hotel in the UK, which will boast 225 rooms and create more than 300 jobs.
Remains of buildings dating as far back as the tenth century pre-date Edinburgh Castle and the creation of the town burgh by David I by about 200 years, while the work has unearthed ditches and walls marking the original boundary of the city. However, some of the discoveries could date as far back as the Bronze Age.
Also discovered at the Cowgate site were a human skull, a drinking vessel, shoes, jewellery, tools and knives, along with a ball used in a giant catapult and an early cannonball.
Hearths, wall panel, structural timbers, rubbish pits and wells have all been unearthed during about 60 weeks of excavations. The Virgin team revealed they were working on the project for the India Buildings on Victoria Street and an adjacent gap site in February of last year, when a 2020 opening date was announced.
However, Virgin Hotels today said work would finally begin on site “within weeks”, with the aim of having all work completed and the hotel opened during 2021.
John Lawson, the city council’s archaeologist, said: “This has been one of the most significant urban excavations ever undertaken in Scotland.
“We have found everything we could have probably hoped to find on an excavation like this. There was basically 1,000 years of archaeology on the site. The full analysis and research has still has to be done, but the results of the work have been tremendous, in terms of scale and quality, and the quality of preservation is outstanding.
“For the first time ever, we have found a series of buildings which pre-date the formation of the medieval town in the 12th century. There are a great sequence of layers on the site, which almost tell the story of Edinburgh in microcosm.”
Raul Leal, chief executive of Virgin Hotels, said: “We always knew India Buildings was a special place and a very special development, though I’m not sure we could have guessed just how amazing it really is. A unique insight has been gained into life in Edinburgh and the city’s development over nearly 1,000 years.
“While we’ve been keen to get on with the development, we know how important it is to take advantage of an opportunity like this to shine a light on the lives and history of the city’s earliest residents and communities. We’re proud to have played a part in work of such national importance. We will look at ways we can inform our guests of the rich history beneath the rooms.”