An archeologist works on uncovering the remains of one of London's earliest theatres, believed to be where a young William Shakespeare trod the boards. (Museum of London/Associated Press)

The theatre where The Merchant of Venice and Romeo and Juliet may have debuted, and where William Shakespeare himself may have performed, has likely been discovered in east London, archeologists at the Museum of London said Wednesday.

The possible foundations of what is known as simply The Theatre were unearthed by builders excavating the site – a vacant garage – for another structure. Museum archeologists were called to the location to make sure nothing was destroyed, and had a eureka moment.

"We were there, scratching our heads, looking into the trenches, thinking, 'This could be it,"' said Jo Lyon, a senior archeologist at the museum. "So we did some more research, and then we found the angled walls. And we all went, 'Oh my gosh, this should be it.' "

Other theatres of similar vintage also have angled walls, so the discovery was significant. Archeologists had known for a long time there was a high probability for The Theatre to be on this particular site. But there are no maps that show its location, no images to show what it might have looked like, and only a vague description of it.

"It's in the right place, it's at the right angle to be a polygonal shape," Lyon said. "It's a pretty high possibility."

The possible discovery of The Theatre, built in 1576 and where Shakespeare's troupe performed in the 1590s, could complete the set of open-air theatres where the Bard's plays were staged. The Rose theatre's location was discovered in 1989 in Bankside, just south of the River Thames in central London, and the Globe theatre is nearby.

A replica of the Globe was built on a site close to the original and opened in 1997.

Shakespeare's company, the Lord Chamberlain's Men, only moved into The Theatre in the 1590s. Until then, they had been performing at the Rose, but a shakeup in the London theatre scene necessitated the move, said Martin Wiggins, a fellow at the Shakespeare Institute at the University of Birmingham.

And in 1597, a dispute with the landlord forced the company to move again, Wiggins said. The company didn't own the ground The Theatre was built on, but Lord Chamberlain's Men did own the material it was built with, so they simply dismantled the entire theatre and moved it south across the River Thames, where it was rebuilt and renamed the Globe.

But The Theatre's foundations remained in east London, and that's what archeologists believe they have found.

"The first thing I want to know it is what the foundations can tell us about the architecture," Wiggins said. "How big was it? How does it compare with the Rose? How does it compare with the Globe? How similar are they?"

Wiggins said an understanding of what the theatre looked like could help Shakespearean scholars understand more about this period in the playwright's history.

"The size of the theatre will have an impact on the way the play is written," he said.

Other works that would have been performed during the period Shakespeare's company was at The Theatre would have included Henry IV, Richard II, King John and The Merry Wives of Windsor, Wiggins said.

Lyon said it's unlikely The Theatre's complete foundations will ever be fully excavated, but her team intends to examine them further.

Fittingly, a new theatre is being built on the site, ensuring the foundations below will be protected.