Counting letters in written texts is a very ancient practice. It has
accompanied the development of Cryptology, Quantitative Linguistics, and
Statistics. In Cryptology, counting frequencies of the different characters in
an encrypted message is the basis of the so called frequency analysis method.
In Quantitative Linguistics, the proportion of vowels to consonants in
different languages was studied long before authorship attribution. In
Statistics, the alternation vowel-consonants was the only example that Markov
ever gave of his theory of chained events. A short history of letter counting
is presented. The three domains, Cryptology, Quantitative Linguistics, and
Statistics, are then examined, focusing on the interactions with the other two
fields through letter counting. As a conclusion, the eclectism of past
centuries scholars, their background in humanities, and their familiarity with
cryptograms, are identified as contributing factors to the mutual enrichment
process which is described here