Many typologies of I.S. archetypes exist in the current literature. But very few rely on long term past perspectives, which could result in a precious opportunity to suggest innovative configurations related to specific institutional environments. On the other hand, historiography is a subject of growing interest in IS. Nonetheless, if many studies have already been carried out on the history of the technology or computer industries, very few have dealt with organizational IS history. This is regrettable, as it would give researchers a unique opportunity to understand long term IS dynamics and to grasp historical IS archetypes. Here, the author outlines a history of the IS of one of the oldest organizations in the world: the Roman Curia (the headquarters of the Catholic Church located within the Vatican). First, the specificities of the object of research (a missionary organization) are explained and methodological details are given. Then, a formal history (pointing out four chronological archetypal IS) is put forward. Lastly, the contributions, limitations and perspectives of this research are discussed.