Snatches of an old American folk song are scribbled across the pages of playwright Stella Kon's notebook. Above the lyrics, "Weep no more my lady", she has sketched in pencil the slender figure of a Peranakan woman.

This became Emily of Emerald Hill, the heroine of one of Singapore's most acclaimed plays.

The story behind Kon's masterpiece is one of many told at the first major exhibition on theatre, organised by the National Library Board (NLB).

Script & Stage: Theatre In Singapore From The 50s To The 80s, which opened to the public yesterday, traces the evolution of local theatre across four languages and four decades.

It showcases more than 100 artefacts such as posters, programmes and handwritten script drafts, culled from NLB's archives or on loan from their owners.

The exhibition's curator, Ms Georgina Wong, 24, hopes the display will shed more light on the roots of drama in Singapore. "There isn't a lot of public knowledge of theatrical history before the 1990s."

The exhibition marks milestones such as Lim Chor Pee's 1962 play Mimi Fan, the first full-length play in English to be put on in Singapore.

Some artefacts chart the fractious growth of the Chinese theatrical scene, which from the 1950s to the 1970s produced several plays with leftist overtones decrying the evils of capitalism.

Traditional Malay theatre forms such as bangsawan and sandiwara sit alongside experimental pieces such as Masuri S. N's 1978 play, Matahari Malam, or The Night's Sun, in which characters break the fourth wall to complain to their author about how they are being written.

The Tamil collection features works by theatre stalwarts such as S.S. Sarma, including his 1966 science-fiction drama Vinvelli Veeran, or The Man From Outer Space, in which an alien race on the moon comes under attack and seeks help from a Singaporean scientist.

Another part of the exhibition in the lobby features iconic Singapore musicals such as Beauty World and Chang And Eng.

Ms Wong and her colleagues spent eight months putting together Script & Stage. "All this may seem like ephemera, things you throw away after the show is over, but they are precious parts of history and people should be saving them," she says.

The exhibition also received items on loan from the families of playwrights such as Kuo Pao Kun, who donated the drafts from Mama Looking For Her Cat, Singapore's first multilingual play.

These notes give an insight into how Kuo crafted the play, which makes use of seven languages and dialects, and also contain sketches of the eponymous cat.

His daughter, Kuo Jian Hong, artistic director of The Theatre Practice, says: "So much has already happened in the past, a wealth that is not given due justice. I hope exhibitions like this help us recognise we stand on the shoulders of giants."