TheCodeBreakers
Bergenroth's success he deliberately hampered the historian's work by
refusing access to such cipher keys as were in his possession.
Bergenroth had to recover them by himself, as well as those keys^ that
had been lost.
The story of his cryptanalytic endeavors can be pieced together from
several of his writings.
I did not go to Spain quite unprepared for my work. I had
carefully studied the Paleographie of Christoval Rodriguez; I have
also spent much time in deciphering such old Spanish documents
as were to be found in the libraries of London and Paris. . . .
[At Simancas.] The first thing I considered it necessary to do
was to study most carefully, not only the Spanish orthography of
the period, but that of each statesman in particular who could be
supposed to have written any of these letters. Even this was not
sufficient. I had to study the turns of thought,
annaabi.ee 
