Nowadays, we pronounce the word legend as "LEDGE-end" (IPA: /ˈlɛdʒənd/). But it looks like at least some people used to pronounce "legend" as "LEE-gend." In A General Dictionary of the English Language, Volume 1, by Thomas Sheridan (1780), the word is transcribed as "le³′‑dzhe¹nd," with the same first syllable as legion "le³′‑dzhu¹n," and in contrast to leger which is transcribed as "le¹dzh′-u¹r".
This pronunciation is also described in Principles of English Etymology: The foreign element, by Walter William Skeat (1891), which lists it among other words from French with "long e":
Le-gend-e, legend; le-gi-oun, legion; re-gi-oun, region.
I checked some modern online dictionaries, but I was not able to find any that mention this pronunciation. However, the Oxford English Dictionary did provide some indirect evidence, as it mentions that one obsolete meaning of the word, "A vast host or multitude," arose due to confusion with the word legion.
I'd like to know when the modern pronunciation first appeared, and when the pronunciation with a long vowel died out.
Best Answer
I still haven't found a definitive answer, but I continued my research and came across the following information that may serve as a partial answer.
John Walker discusses the pronunciation of this word in his Critical Pronouncing Dictionary (1791). He prescribes the long vowel, but mentions the pronunciation with the short vowel:
Interestingly, he recommends the short vowel for legendary:
So this establishes that the modern pronunciation existed at least as early as 1791. I still don't know how late the pronunciation with a long vowel was used (although the citation from Skeat in my question gives a lower bound of 1891).