Vacant world middleweight title · 15 rounds

Jack
Twin Sullivan
VS
Philadelphia
Jack O'Brien

O'Brien · PTS 15/15

Dec 22, 1903 · Criterion A.C., Boston, 🇺🇸

Sullivan going in0-1-0

O'Brien going in108-6-16

Confirmation✓ one source

MethodPTS

Round15 of 15

TitleVacant world middleweight title

Sources

English Wikipedia
side b · observed 2026-10-11
en.wikipedia.org/wiki/Philadelphia_Jack_O'Brien

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