Story highlights Digging has begun at the Bedlam burial ground in London

Taking its name from a hospital for the mentally ill, Bedlam is now a synonym for chaos

London (CNN) Archaeologists have started excavating about 3,000 skeletons from the Bedlam burial ground in London, used from 1569 to at least 1738.

Also known as Bethlem and the New Churchyard, more than 20,000 Londoners are believed to have been buried there. The ground was used by "a varied cross-section of society throughout the years since the burial ground was open," Nick Elsden, project manager from MOLA (Museum of London Archaeology) told CNN.

And they include those who could not afford a church burial or chose to perish there for religious or political reasons. The ground also contained the overflow of bodies when other cemeteries became full. Bedlam, now a synonym for chaos, took its name from the Hospital of St Mary of Bethlehem in London which nursed the mentally ill.

Photos: London's ancient burial ground is excavated Photos: London's ancient burial ground is excavated Archaeologists have started excavating about 3,000 skeletons from the Bedlam burial ground in London, used from 1569 to at least 1738. Hide Caption 1 of 6 Photos: London's ancient burial ground is excavated Also known as Bethlem and the New Churchyard, more than 20,000 Londoners are believed to have been buried there. The ground was used by "a varied cross-section of society throughout the years since the burial ground was open," Nick Elsden, project manager from MOLA (Museum of London Archaeology) told CNN. Hide Caption 2 of 6 Photos: London's ancient burial ground is excavated And they include those who could not afford a church burial or chose to perish there for religious or political reasons. It also contained the overflow of bodies when other cemeteries became full. Bedlam, now a synonym for chaos, took its name from the Hospital of St Mary of Bethlehem in London which nursed the mentally ill. Hide Caption 3 of 6 Photos: London's ancient burial ground is excavated A team of 60 archaeologists will work six days a week on the project, expected to finish in September this year. Hide Caption 4 of 6 Photos: London's ancient burial ground is excavated The site was found at an entrance of the city's new Liverpool Street Crossrail station -- part of a £14.8 billion ($22 billion) project that will expand London's railway network. Hide Caption 5 of 6 Photos: London's ancient burial ground is excavated Elsden said the excavation tells us a great deal about how Londoners lived from the 16th to the 18th century. "A large sample of the population from that period will enable us to look at the lifestyle, looking at Roman London and what the Romans were doing in the suburb area, outside the city walls." Hide Caption 6 of 6

Among the deceased are victims of the English Civil War, the Great Plague of 1665 and the Great Fire of London in the following year.

The site was found at an entrance of the city's new Liverpool Street Crossrail station -- part of a £14.8 billion ($22 billion) project that will expand London's railway network.

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