This revisionist article argues the case for recognizing a short-lived military dictatorship in 1922 in southern Ireland under the revolutionary leader Michael Collins. Central to understanding this situation, and how it came about, is the identification of a secret Irish Republican Brotherhood–Free State diarchy from February 1922 that evolved into a military government in July after the beginning of the civil war. This reinterpretation makes four claims. First, it challenges assumptions about the structure of power under Collins while he was commander-in-chief of the Free State army. Secondly, it re-evaluates Collins's role as an icon of southern Irish nationalism associated with constitutionalism and democracy. Thirdly, it questions part of the foundation myth of the southern Irish state, which assumes independence was achieved in 1922 by an uninterrupted, constitutional process. Fourthly, it calls into question the methodologies applied by historians defending this constitutional interpretation. Since 1970 the historiographical context of a grand constitutional narrative of southern state formation has been war in Northern Ireland. In response to this event, it is suggested, historians have emphasized the Irish state's democratic origins so as to define southern experiences in 1922, against the Provisional IRA's unmandated attempt at violent state formation. This has contributed to distortions in both historical method and interpretation.