The exact composition of the ministry and the secretary's duties changed several times over the Early Modern period, but in general, the Département de la Maison du Roi oversaw four main areas: the "Maison du Roi" ("Household of the King"), the "Bâtiments du Roi" ("Buildings of the King"), the General Affairs of the Clergy, (from 1749 on) Affairs of the RPR ("Religion Prétendue Réformée", i.e. the Huguenots), and the administration of the capital city of Paris and the provinces.
In 1669, Jean-Baptiste Colbert bought the post from Henri de Guénégaud du Plessis-Belleville, and thus combined under his control the Maison du Roi with the Department of the Navy and the position of Contrôleur général des finances (chief financial officer of the realm).
The "Maison du Roi" (Household of the King) was the name of the military, domestic and religious entourage around the Royal Family in the Kingdom of France.
The Secretary also oversaw (either directly or through the service of the Bâtiments du Roi) cultural and scientific institutions such as the Bibliothèque du Roi, the Paris Observatory, the Jardin des Plantes, the Collège royal, French academies and royal entertainment.
The Secrétaire d'État à la Maison du Roi was also in charge of the policing and general administration of French provinces (at first those with provincial estates or "pays d'état", and eventually over all other internal provinces), except for border regions (which were supervised by the Department of War).