Today I learned that the idiom “stealing thunder” has a surprisingly literal background.
In 1709, a dramatist by the name of John Dennis invented the “thunder sheet” for a tragedy he had written called “Appius and Virginia”. Simply described, the thunder sheet (sometimes called a “thunder machine”) is a thin sheet of metal that is shaken or struck with a mallet to produce a thunder-like sound effect for musical or dramatic purposes.
While the play he invented the machine for was successful, his next play did not enjoy the same success and was eventually discontinued and replaced by another play. Mr Dennis happenede to stop by said replacement play and found, to his surprise, that discovered that it made use of his thunder sheet for dramatic effect. This upset him greatly (who can blame him!) and is said to have cried out something along the lines of ““Damn them! They will not let my play run, but they steal my thunder!””.
And just like that, the term was rightfully off to the proverbial races.
Now you know!