The Chief of Staff of the IRA was Richard Mulcahy, who was responsible for organising and directing IRA units around the country. In theory, both Collins and Mulcahy were responsible to Cathal Brugha, the Dáil's Minister of Defence, but, in practice, Brugha had only a supervisory role, recommending or objecting to specific actions. A great deal also depended on IRA leaders in local areas (such as Liam Lynch, Tom Barry, Seán Moylan, Seán Mac Eoin and Ernie O'Malley) who organised guerrilla activity, largely on their own initiative. For most of the conflict, IRA activity was concentrated in Munster and Dublin, with only isolated active IRA units elsewhere, such as in County Roscommon, north County Longford and western County Mayo.