A previously undiscovered 1,600-year-old burial site in northern England could provide key clues about a a largely undocumented period in British history, officials announced this week. 

The government in Leeds, a city about an hour northeast of Manchester, announced Monday that archeologists had unearthed a historic cemetery in the area thought to contain the remains of more than 60 men, women and children who lived there more than a millennium ago. 

Among the archaeologists' finds was a particularly noteworthy discovery: an ancient lead coffin that is believed to hold the remains of an aristocratic woman from the later years of the Roman Empire. 

The site appeared to include remains of Roman and Anglo-Saxon people, the city of Leeds said in a news release, noting that different burial customs associated with each cultural group indicated some remains may be traced back to the late Roman Empire and early Anglo-Saxon kingdoms that emerged after it. Archeologists made the discovery while working on a wider dig near Garforth in Leeds in the spring of last year, the city said. 

Officials had kept the news of their discovery under wraps in order to protect the site's anonymity while initial tests were underway to learn more about the archaeological finds and their significance, according to the city. Now that the dig is complete, experts will analyze the remains and use carbon dating to establish more precisely how old they are, officials said. Remains will also undergo "detailed chemical tests which can determine extraordinary details such as individual diets and ancestry."

The ancient burial site in Leeds could ultimately help clarify details about an important stretch of British history, when the Roman Empire transitioned to subsequent Anglo-Saxon communities.

"Archaeologists hope this means the site can help them chart the largely undocumented and hugely important transition between the fall of the Roman Empire in around 400AD and the establishment of the famed Anglo-Saxon kingdoms which followed," the city of Leeds said in its announcement this week. 

The findings could be especially illuminating for Leeds, where the land once belonged to an ancient kingdom called Elmet that historians say existed from the end of Roman rule in Britain through centuries of Anglo-Saxon settlements.

"Even after the Romans had gone, many areas were still very much a mixture of the two cultures—including Elmet," said Stuart Robinson, a spokesperson for the Leeds City Council, in an email to CBS News.

"And that's part of the reason that you see a mixture of both Roman and Saxon/British cultures in the burial customs at the site," Robinson said. "So the hope is that once they're analysed, these finds will give a clear picture of how the Saxon culture in Yorkshire (and Britain) evolved."

Roman Britain was a period that lasted nearly 400 years at the beginning of the current era, when large parts of the island were occupied by the Roman Empire. Although the occupation left a significant mark on British culture, the eventual transition from the Roman occupation to Anglo-Saxon settlements remains a little-known stretch of British history.

"This has the potential to be a find of massive significance for what we understand about the development of ancient Britain and Yorkshire," said David Hunter, the principal archaeologist with West Yorkshire Joint Services, in a statement included with this week's announcement from the city of Leeds. Yorkshire is the county where Leeds is located.

"The presence of two communities using the same burial site is highly unusual and whether their use of this graveyard overlapped or not will determine just how significant the find is. When seen together the burials indicate the complexity and precariousness of life during what was a dynamic period in Yorkshire's history," Hunter's statement continued. "The lead coffin itself is extremely rare, so this has been a truly extraordinary dig."

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• Archaeologist
• Britain