On September 12, 1919, the British government, acting through the Lord Lieutenant of Ireland Sir John French, declares Dáil Éireann — the revolutionary parliament of the Irish Republic — illegal. The proclamation categorises the Dáil as a “dangerous organisation” and adds it to a list of banned groups, which also includes Sinn Féin, the Irish Volunteers, Cumann na mBan, and the Gaelic League.

The ban comes after just eight months of Dáil Éireann’s existence, which begins on January 21, 1919, when Sinn Féin MPs refuse to take their seats in Westminster and instead convene a separate parliament in Dublin. The British initially underestimate its significance, but events change rapidly.

Sinn Féin’s attempt to raise funds (the Dáil Loan) in August 1919 for the republican cause is seen as a move to legitimise an independent administration, undermining British control. Also, some Irish Volunteers members swear allegiance to Dáil Éireann, which is seen as a political act with potential to inspire wider resistance. The summer of 1919 also sees a surge in attacks, prompting Dublin Castle to respond with suppression measures.

The proclamation takes effect nationwide, including all counties and major boroughs such as Dublin, Belfast, Cork, Limerick, Derry, and Waterford. Within days, police raids and searches target Sinn Féin headquarters and members’ homes. The Harcourt Street headquarters in Dublin is raided, leading to arrests of figures like Patrick O’Keefe and Ernest Blythe. Similar searches occur in Belfast, Derry, Omagh, and Ballycastle, uncovering literature, weapons, and ammunition in some cases.

The ban is a major blow to Sinn Féin’s political prestige, but it also hardens the resolve of many republicans. Historians note that the suppression turned some moderate politicians into “extremists” and increased the likelihood of militarisation. Despite the crackdown, the Dáil continues to operate in secret, meeting in multiple Dublin locations to maintain the Irish Republic’s political legitimacy.

In short, the September 12, 1919 declaration marks a turning point in the Irish War of Independence, shifting the conflict from political negotiation to open confrontation.

(Pictured: Members of the First Dáil Éireann seated and standing outside the Mansion House in Dublin on January 21, 1919)