The earliest reference discussed in this thread is the 1930s unless you go with a Cobb quote (although he apparently did not confirm that players actually used the term triple crown back in the early 1900s):
http://www.baseball-fever.com/archiv...p/t-29308.html
The relevant posts:
ONE
"One of the earliest references I found in regards to the triple crown centers on the 1906 World Series. A Washington Post writer surmised that the White Sox had won the triple crown - that is - champions of Chicago, the American League and the World Series.
The term "Triple Crown" doesn't seem to have gained use by sportswriters in relation to baseball until 1941. In a Christian Science Monitor article on 7/3/1941 there is a discussion about "DiMaggio shooting at Triple Batting Crown(BA,HR,RBI)."
And then articles noting Williams' accomplishment in 1942."
TWO
"I tried a search on Sporting News. It's first reference to a triple crown was July 9, 1936, pp. 5. Was saying that Lou Gehrig was insisting he would win the 'triple crown again', as in 1934.
I tried the New York Times, and it talks about triple crowns in horse racing as early as 1923. But no baseball references until the 1940's. "
THREE
ty cobb mentions in his autobiography (the one with Stump) that back in the early 1900s (before the HR was revolutionized), the triple crown was recognized as having the highest BA, most RBIs and most hits