Originally posted by homedepotov
Did Ruy Lopez actually really invent the en passant capture? If so, why is the word "en passant" a french word? GM Larry Evans credits him with it, but I don't think of him (Evans) as a good source of chess facts, since he has been accused of plagiarizing in the past.
This fact sure isn't mentioned in chessgames.com's biographical sketch of Ruy Lopez.
If you want a source, you need to avoid tertiary sources altogether. The best secondary sources quote directly from primary sources. H.J.R. Murray, History of Chess
(1913) remains the best secondary source on most matters of chess history. Marilyn Yalom, Birth of the Chess Queen
(2004) is exceptional for many matters medieval.
Murray notes that Ruy Lopez describes the en passant
move in his text of 1561 (p.461). He does not credit the Spanish friar with invention of the move. The fine point between description of existing practice and invention is precisely the sort of slop that is Evans' modus operandi
. Never trust him on any matter of history to which he is not a direct witness. Even then, be careful, especially if it concerns Soviet era chess politics and Bobby Fischer.
I wrote a little about this history last December: http://chessskill.blogspot.com/2011/12/en-passant-history-and-illustration.html