This pocket watch was given by Seán MacDiarmada to his friend Barney Mellows (brother of Liam Mellows) in Room 46 of Richmond Barracks on 8th May, a few days before his execution. Mellows had it inscribed ‘VIII/V/1916’ in memory of that day.

Mac Diarmada (MacDermott), Seán (1883–1916), republican revolutionary, was born January 1883 (baptised 29 January) in Corranmore (Laghty Barr), Kiltyclogher, Co. Leitrim.

Joining a Dungannon club (1905), he met members of the secret Irish Republican Brotherhood (IRB). Sworn into the IRB (1906), he joined eagerly in the reinvigoration of the body's Belfast organisation. When the Dungannon Clubs amalgamated with the Cumann na nGaedheal organisation of Arthur Griffith to form the Sinn Féin League (April 1907), Mac Diarmada became an organiser for the new body, founding local branches initially throughout Ulster and then nationally (1907–11).

In 1908, Mac Diarmada was appointed the brotherhood's national organiser. He moved with Hobson to Dublin, where they allied with IRB veteran Thomas Clarke, recently returned from America, in urging a more active policy upon the semi-moribund organisation. He was manager of the monthly journal Irish Freedom (November 1910–December 1914), an initiative of McCullough and Clarke launched under the cover of the Dublin Wolfe Tone Clubs committee, and intended to express IRB opinion.

He was imprisoned for four months in Mountjoy jail (May–September 1915) after making a vigorous anti-recruiting speech to a Volunteer meeting at Tuam, Co. Galway.

On his release he and Clarke joined the secret military council – already consisting of Pearse, Joseph Plunkett, and Éamon Ceannt – assembled by Clarke during Mac Diarmada's imprisonment to devise the detailed plans for the rebellion. Amid a concurrent reorganisation of the IRB supreme council, Mac Diarmada engineered the election of the Belfast-based Denis McCullough as president, thereby securing his and Clarke's unimpeded control of the executive.

Throughout the early months of 1916 Mac Diarmada was at the centre of the final logistical preparations for the rising. His role in the confused events immediately preceding the rising was critical. He and Plunkett most likely instigated circulation of the ‘Castle document,‘ a purported leak suggesting an imminent government move to disarm the Volunteers, which conveniently supplied a plausible cover before the eyes of the Volunteers’ moderate leadership for the final mobilisation activity. On Good Friday morning (20 April) Mac Diarmada persuaded Volunteer commander-in-chief Eoin MacNeill, who had learned the previous evening of the plan to rise on the Sunday, that the insurrection should proceed because the expected arrival of German arms made likely a government move to suppress the movement, but also increased the prospects for success. Mac Diarmada ordered the temporary detention of Hobson that evening, fearing his interference with the conspirators’ intentions.

As a member of the provisional government into which the military council now transformed itself, Mac Diarmada signed the proclamation of the republic. Throughout the rebellion he remained, in civilian clothes, with the headquarters garrison in the General Post Office, functioning as adjutant to Connolly (the commander-in-chief), and coordinating the operation of a field hospital in the building. From the Thursday evening, as Connolly weakened from wounds, Mac Diarmada and Clarke, though neither held officers’ rank in the Volunteers, increasingly commanded the direction of the battle. Mac Diarmada ordered evacuation of the wounded to Jervis Street hospital on the Friday, and amid the confused evacuation of the burning GPO, rallied the troops to continue the manoeuvre in the face of withering hostile fire. With Pearse in military custody after agreeing to surrender on Saturday afternoon (29 April), Mac Diarmada read the surrender order to the garrison in the new headquarters in a Moore St. shop, adding his own commendation of their gallantry. With calm logic, he quelled a section of the garrison who wished to fight on, stressing their duty to survive the rebellion, so as to some day ‘finish the job’.

At his court-martial (9 May) he conducted a spirited defence, challenging prosecution evidence, cross-examining witnesses, and demanding that all allegations against him be proved. Found guilty of participation in armed rebellion, he was acquitted on a lesser charge of causing disaffection among the populace. He and the severely wounded Connolly were the last two of the rebellion leaders to be executed by firing squad in the yard of Kilmainham jail (12 May), despite growing public disquiet, and protests by British and Irish politicians (both nationalist and unionist).

(Biographical details: Lawrence William White. 'Mac Diarmada (MacDermott), Seán'. Dictionary of Irish Biography.)