The Seminary was created by Pope Eugene III in the twelfth century as an apostolic palace and summer residence due to the importance of Segni and its panoramic position near the cathedral. Over the centuries there many important popes in the history of the Church have stayed here.

Today a wing of the seminary houses the Innocent III Historical Archive which collects and makes available to scholars the papers of the Episcopal Chancery of Segni, the Chapter of the Cathedral, the Seminary and some parishes of the Diocese.