1) Roberto Duran
2) Pernell Whitaker
3) Benny Leonard
4) Joe Gans
5) Barney Ross
1. Roberto Duran
2. Benny Leonard
3. Joe Gans
4. Henry Armstrong
5. Tony Canzoneri
Hey matt
I have to disagree with Roberto being number 1
its probably Henry Armstrong
1. Henry Armstrong
2. Roberto Duran
3. Sam Langford
4. Joe Gans
5. Benny Leonard
1. Roberto Duran
2. Sugar Ray Robinson---he started at 135 lbs. too and won his first 20 or so fights there beating champions Fritzie Zivic and Sammy Angott and veteran campaigners Marty Servo and Izzy Janazzo many times in an impressive unbeaten run that ended only when he lost the second fight of his historic series with archrival middleweight Jake La Motta
3. Benny Leonard
4, Julio Cesar Chavez/Joe Gans
5. Lou Ambers/Barney Ross
Henry Armstrong fought mainly in the featherweights and welterweights and had just few fights at lightweights the most prominent his two fights with Lou Ambers which he won the first to win the world title at 135 lbs. after he had won the welterweight crown first which he lost back to Ambers immediately in their rematch. After that loss to Ambers, Armstrong decided to fight full time at welters. he also lost to former lightweight champions Fritzie Zivic and Beau Jack later in his career although he beat forner titlists Sammy Angott and Juan Zurita.
Roberto Duran is surely number 1, and Joe Gans and Benny Leonard somewhere behind him in no particular order. But I'm curious to see the rest.