Archaeologists digging at the site of the Curtain Theater, a 16th-century playhouse where some of Shakespeare's plays were staged, have unearthed a fragment of a ceramic bird whistle that was possibly used as a sound effect device.
"Bird whistles were children's toys, but in this context may have been used for sound effects in theatrical performances," the Museum of London Archaeology (MOLA) wrote in a statement.
In Shakespeare's Romeo and Juliet there are several references to bird song, such as "That birds would sing and think it were not night."
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Found in 2011 behind a pub in Shoreditch, east London, the remains of the Curtain have revealed other intriguing findings.
According to MOLA archaeologists, the playhouse, which opened in 1577, was rectangular - not round or polygonal like most Elizabethan theaters.
They found wall remains up to five feet high, revealing the venue measured some 72 feet by 100 feet and could hold about 1,000 people.
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"Our archaeologists have been able to identify the courtyard, where theatregoers stood, and the inner walls, which held the galleries where wealthier audience members would have sat," MOLA said.
Built some 200 yards south of The Theater, London's first playhouse which had opened a year before, The Curtain was believed to have staged the premier of Shakespeare's Henry V.
However, in the opening verses of the play, the playhouse is described as "this wooden O."
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This leaves scholars with two hypothesis: either Henry V was first staged at the Globe or it may still have premiered at the Curtain in 1599, but without the prologue.
MOLA archaeologists will continue to excavate the site for another month.
The Curtain's foundations will then remain on permanent display alongside the unearthed finds as part of a visitor center at the heart of a major redevelopment called The Stage, which will include shops, restaurants and more than 400 homes.