From the site of the Institute of the Good Shepherd:
On 8 September 2006, the Institute of the Good Shepherd was formed as a society of apostolic life in full communion with the Holy See.
The specificity of the Institute of the Good Shepherd (IBP), that is what constitutes its raison d’être, lies in the mission entrusted by the Holy See to defend and disseminate the Catholic Tradition in all its aspects : doctrinal, apostolic and liturgical. Thus, the IBP proposes to form priests according to the liturgical and theological tradition at the disposal of the Church.
In their life this is implemented by the exclusive use of the Traditional Roman Rite (according to the liturgical books in force in 1962, also called the “extraordinary form of the Roman rite”) in all its liturgical acts. Thus, the IBP seeks to spread this liturgical treasure of the Church to all the Catholic faithful, to help the Church in her mission of re-evangelization of the present world.
Such a mission, within the IBP, is concretized by a traditional spiritual, philosophical and theological formation, especially according to the theology of St. Thomas Aquinas, so much recommended by the Sovereign Pontiffs. This mission also resides in the possibility explicitly given by the Holy See of a serious and constructive criticism of the controversial acts of the recent magisterium, according to the theological principles which order the various degrees of magisterium and the assent that is their due. This is not done in order to cause a vain polemic, but rather to provide the ecclesiastical authorities with sound theological arguments for the correct interpretation or, as the case may be, the correction of these texts.
Following this concern to guarantee a solid academic formation, the seminarians of Courtalain have the possibility (after finishing the six years of formation in the seminary) to obtain the canonical baccalaureate of Theology by the Catholic Institute of Toulouse. In addition, most of the young priests ordained at the IBP continue their academic training by presenting master’s degrees and doctorates in theology, philosophy, canon law, and so on. Finally, always seeking to accomplish its mission, the Institute offers symposiums and lectures on various topics of theology and philosophy, with a view to having an active voice in the current theological debates. Thus, for example, between 2006 and 2015 the members of the IBP proposed, in France, symposiums on various subjects: liturgy, tradition or mutation, questions of Thomistic ontology. The apostolate of the Institute can be developed in various circles: personal parishes, but also by chaplaincies, schools, by the preaching of retreats, by works of charity, formations for priests and laymen, etc. All of this for the good of souls can be part of the ministry of a priest of the IBP.