Founded on 24 August 1985,[5] the group was formed by Catholic priests affiliated with the Parroquia de San Félix Africano, who espoused the integralist teachings of Marcel Lefebvre, alongside notable figures from the Hermandad Sacerdotal Española.

The main targets of the group were Catalan independence-related associations and independentist organizations, such as the Moviment de Defensa de la Terra, the most prominent extra-parliamentary political expression of the independence movement, and Terra Lliure, a far-left terrorist organization;[9] but Milícia Catalana also attacked clinics where abortions were practiced (in 1989, the Dexeus Clinic's façade was damaged by an explosion attributed to the organisation.

[2] The ideology of Milícia Catalana was deeply rooted in Catholic integralism and Spanish unionism,[17] drawing significant inspiration from Marcel Lefebvre's teachings.

[20] Their actions were strategically directed towards supporting an "armed struggle",[21] primarily targeting Catalan nationalist and separatist organizations, as well as bookstores associated with these movements.

[22] This led them to focus their activities on venues promoting Catalan nationalism, such as independentist gatherings, along with establishments like sex shops, gay bars and saunas, and abortion clinics, which they vehemently opposed on moral grounds.