Denis McCullough (Irish: Donnchadha Mac Con Uladh; 24 January 1883 – 11 September 1968) was a prominent Irish nationalist political activist in the early 20th century.McCullough was born at 1 Barrack Street, Belfast, on 24 January 1883, to Daniel McCullough, a publican, and Margaret Magee.McCullough was a separatist nationalist from an early age.Both his father and grandfather were in the Irish Republican Brotherhood (IRB), as was his brother. When he was 17, his father had him inducted into the Irish Republican Brotherhood (IRB) at the side door of a pub by a man who seemed to view the ritual as an unpleasant distraction to a night of drinking. The event disillusioned McCullough with the IRB, and he took it upon himself to revitalise the organization, with assistance from, among others, Bulmer Hobson and Seán Mac Diarmada. The trio founded the Dungannon Clubs as a non-sectarian, republican, separatist organization (it was later absorbed into Sinn Féin), for recruitment. They worked to remove "armchair republicans" from positions of power. Their cause prospered with the return of veteran Fenian Tom Clarke to Ireland in 1907. Wikipedia