Martin McGuinness's appearance at the Saville Inquiry yesterday marked a significant and historic day not just for the tribunal but also in the history of the IRA.
For the first time in the history of the movement, a senior IRA figure willingly took his place in a British legal arena to outline details of the organisation as it existed in Derry in 1972.
The importance of the occasion was not lost as a huge media presence descended on Derry's Guildhall for the 390th day of the Saville Inquiry.
Journalists crammed into a packed press centre and Calgach Centre to hear Mr McGuinness outline his reasons for coming before a British law lord and two Commonwealth judges.
Mr McGuinness said he came willingly to the Inquiry to help the Bloody Sunday families uncover the truth behind the deaths of their loved ones.
Once inside, a series of sharp exchanges erupted between the Mid-Ulster MP and counsel to the Inquiry, Christopher Clarke QC over the relevance of some of the questions being put.
Mr McGuinness said he initially believed based on the Widgery experience that a British law lord could not find the truth behind Bloody Sunday.
He eventually told the Inquiry he was in the Official IRA for a number of weeks before transferring to the Provisional IRA and that he became Officer Commanding of the Provos in Derry a fortnight after Bloody Sunday.
The day did not go by without its lighter points. Mr McGuinness told the Tribunal that before Bloody Sunday he "unfortunately" did not have any moles in Victoria or Ebrington police and army barracks "at that stage".
He was warned that his failure to disclose the whereabouts of a house in which the IRA stored arms on Bloody Sunday could lead to the suggestion that he had something to hide.
Mr McGuinness said he was bound by a "code of honour" and felt it would be an act of betrayal to disclose the identity of the householders. But he agreed to ask them if they would allow their names to be revealed. The Sinn Féin MP told the Inquiry he was sure no Provisional IRA members engaged militarily with British soldiers on Bloody Sunday although a number of shots were fired at an army base on Derry's walls long after the Parachute regiment left the Bogside.
He saved his most damning criticisms for former IRA man Paddy Ward and Sunday Times journalist Liam Clarke. Mr Ward testified last week that Mr McGuinness was present when he, as a member of the Fianna, was given detonators for nailbombs for use on Bloody Sunday.
Mr Clarke who was present yesterday is co-author of an unauthorised biography of the Derry politician in which Mr Ward's claims where initially carried. Each of the claims made by the men and others in Mr Clarke's book were dismissed by Mr McGuinness as "a bucketful of lies" or not having a "smidgen of truth".
As he left the Inquiry for the day, Mr McGuinness was pursued by a raft of cameras and their accompanying operators not seen in Derry since the height of the Troubles.
The media circus is expected to continue today when Mr McGuinness will be questioned by lawyers for the British military, Paddy Ward and Liam Clarke.