Excavations for London's Crossrail project have unearthed bodies believed to date from the time of the Black Death.
A burial ground was known to be in an area outside the City of London, but its exact location remained a mystery.
Thirteen bodies have been found so far in the 5.5m-wide shaft at the edge of Charterhouse Square, alongside pottery dated to the mid-14th Century.
Analysis will shed light on the plague and the Londoners of the day.
DNA taken from the skeletons may also help chart the development and spread of the bacterium that caused the plague that became known as the Black Death.
Charterhouse Square lies in an area that was once outside the walls of London, referred to at the time as "No-man's Land".
The skeletons' arrangement in two neat rows suggests they date from the earliest era of the Black Death, before it fully developed into the pandemic that in later years saw bodies dumped haphazardly into mass graves.
Archaeologists working for Crossrail and the Museum of London will continue to dig in a bid to discover further remains, or any finds from earlier eras.
The £14.8bn Crossrail project aims to establish a 118km-long (73-mile) high-speed rail link with 37 stations across London, and is due to open in 2018.
Because of the project's underground scope, significant research was undertaken into the archaeology likely to be found during the course of the construction.