Bone analysis will tell us about her diet

Archaeologists discovered a complete skeleton when they lifted the lid on Wednesday evening at the Museum of London.

The elaborate nature of the coffin and items left in the grave have led archaeologists to believe the skeleton could be that of the most important Roman person ever found in Britain.

The museum's director, Dr Simon Thurley, said leaves dating back to Roman London were found at the bottom of the coffin - a find he described as "totally astonishing".

Rachel Ellison reports from the Museum of London: "A very exciting find"

How the leaves got into the coffin is still a mystery, although some were speculating that they could have formed a funereal garland.

"People last night were saying they could be olive leaves which would be rather extraordinary if that were the case," Dr Thurley told BBC Radio 4's Today programme.

"Or perhaps it was some wonderful romantic moment when a gust of wind one autumn blew the the leaves across and they tumbled into the coffin. We just don't know yet."

Dr Simon Thurley: Discovery of leaves in the coffin is "totally astonishing"

He said the archaeologists were most excited by the inch of mud in the bottom of the coffin, suggesting it may have been waterlogged.

This layer could preserve organic matter and jewellery.

Scientists wore protective suits

Dr Thurley said the left arm of the skeleton was folded across the chest, suggesting a Christian burial. But the ornate scallop shell decoration on the outside of the lead coffin had been thought to be pagan symbols, a sign of what he called "an interesting insurance policy".

Unearthed in the heart of London

The stone sarcophagus, with a sealed lead coffin inside, was buried in the early fourth century. It was uncovered a few weeks ago in a Roman cemetery at Spitalfields Market near the City of London.

The London Museum's archaeological team wore protective suits and masks to open the coffin, in case any bacteria or toxic vapours were released.

The BBC's Sancha Berg describes the moment the coffin lid was opened

Scientists worked through the night analysing the find, and more details are expected to be released on Thursday.

It is hoped that DNA tests will establish exactly where the woman - thought to be in her early 20s - came from.

There were no immediate clues to her identity, but archaeologists said further investigation into the coffin's interior might reveal more.

Insight into VIP Romans

Burying such a heavy object around the start of the fourth century AD would have been a rare and expensive event. And the coffin itself is expected to give new insight into the ruling class of Roman London.

"This coffin without doubt belongs to someone very important," says Dr Thurley. "We know a huge amount about Roman London, but very little about the very, very important people who governed it."

The coffin was found under Spitalfields Market

Very valuable "grave goods" have already been found alongside the sarcophagus. These were placed to help the deceased on their journey into the afterlife.

What we found is very interesting and is unique to this country," Jenny Hall, the museum's Roman Curator told BBC News Online. "Amongst other things, we found a little jet box and a long glass flask which probably would have held perfumed ointments."

The bones themselves will, after analysis, reveal the diet and health of rich Roman Londoners.

Members of the public can view the continuing work on the coffin and the skeleton at the Museum of London until 24 April.