Immensa Aeterni Dei is an apostolic constitution in the form of a papal bull issued by Pope Sixtus V on 22 January 1588. The constitution reorganized the Roman Curia, establishing permanent congregations of cardinals to advise the pope on various subjects. The primary role of the document was to provide instruction in condemning or correcting literature which were against Catholic doctrine. The document also had the authority to give permission for selected individuals to read books which were forbidden. It has since been superseded, most recently by Pope John Paul II's constitution Pastor Bonus.
The formation of congregations
The immense Immensa Aeterni Dei called for the formation of 15 permanent congregations:
References
Immensa Aeterni Dei Wikipedia(Text) CC BY-SA