So Now You Know

Close your eyes and let those gently lilting lyrics sung by Gene Autry run through your mind ...

You know Dasher and Dancer
And Prancer and Vixen,
Comet and Cupid
And Donner and Blitzen...

Or maybe those words by "Clement Clarke Moore",

Now Dasher! now, Dancer! now, Prancer and Vixen!
On, Comet! on, Cupid! on, Donner and Blitzen!

But wait ... turns out the original 1823 poem “A Visit from Saint Nicholas” by Henry Livingston, Jr. reads

Now Dasher! now, Dancer! now Prancer and Vixen!
On, Comet! on, Cupid! on Dunder and Blixem!

Only in later versions, modified by Moore in 1844, were the two names changed to German: Donder (close to Donner, thunder) and Blitzen (lightning), to better rhyme with "Vixen". Finally, for some reason, in the song "Rudolph the Red-Nosed Reindeer" Johnny Marks turned "Donder" into "Donner". Since 1950 or so, the two reindeer names have been Donner and Blitzen in both the “Rudolph” song and the “Visit” poem.