be still, my beating heart !

The expression, and the comic manner in which it is now delivered, were brought to a wide public in Gilbert and Sullivan’s opera HMS Pinafore, 1878:

Ralph:
Aye, even though Jove’s armoury were launched at the head of the audacious mortal whose lips, unhallowed by relationship, dared to breathe that precious word, yet would I breathe it once, and then perchance be silent evermore. Josephine, in one brief breath I will concentrate the hopes, the doubts, the anxious fears of six weary months. Josephine, I am a British sailor, and I love you!

Josephine:
Sir, this audacity!
(Aside.) Oh, my heart, be still my beating heart!
(Aloud.) This unwarrantable presumption on the part of a common sailor!

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