Cumann na mBan (Irishwomen’s Council), at the behest of Constance Markievicz, votes overwhelmingly to reject the Anglo-Irish Treaty on February 5, 1922. During the Irish Civil War, over 400 members of the movement are arrested by the Irish Free State Government.
Cumann na mBan is an Irish republican women’s paramilitary organisation formed in Dublin on April 2, 1914, merging with and dissolving Inghinidhe na hÉireann and, in 1916, it becomes an auxiliary of the Irish Volunteers. Although it is otherwise an independent organisation, its executive is subordinate to that of the Volunteers.
On January 7, 1922 the Anglo-Irish Treaty is approved by the Second Dáil by a close vote of 64–57. On February 5 a convention is held to discuss this, and 419 Cumann na mBan members vote against as opposed to 63 in favour. In the ensuing Civil War, its members largely support the anti-Treaty Republican forces. Over 400 of its members are imprisoned by the forces of the Provisional government which becomes in December 1922 the Irish Free State. Some of those who support the Treaty change the name of their branches to Cumann na Saoirse, while others retain their name but give allegiance to the Free State Government.
Cumann na mBan continues to exist after the Treaty, forming (alongside Sinn Féin, the Irish Republican Army, Fianna Éireann and other groups) part of the Irish republican milieu. The government of the Irish Free State bans the organisation in January 1923 and opens up Kilmainham Gaol as a detention prison for suspect women.
Its membership strength is adversely affected by the many splits in Irish republicanism, with sections of the membership resigning to join Fianna Fáil, Clann na Poblachta and other parties. Máire Comerford, a lifelong member from 1914, reflects in later years that it became a “greatly weakened organisation” that “gathered speed downhill” from the founding of Fianna Fáil in 1926.