First two-weight class champion.

[VG_Addict]

Who was the first boxer to win a world title in TWO weight classes? By that, I mean, he won a world title, moved up in weight, and won a world title in that weight class.

[NChristo]

George Dixon was first name to come to mind, he was the first black champ and held the Bantamweight world title in 1890 and Featherweight in 1891. Probably someone earlier though.

[dan_cov]

Bob Fitzsimmons I think..

[Salardo]

maybe Gene Tunney or Bob Fitzsimmons?
both won the LH title and then won the Heavyweight crown as well.
But I don't know who the first in history was.
EDIT: I just looked it up. Actually Fitzsimmons won the Middleweight title in 1891 and then in 1896 the Heavyweight title and a few years later did he win the light heavyweight title. (the LH division only exists since 1903)

[Bolo Punch]

AFAIK it was Bob Fitzsimmons.