The Seminario Palace is part of the monumental complex of the Minerva, which rises on the very same site where, in ancient Rome, there stood the temple of Chalcidician Minerva and the temple dedicated to Isis and Sarapis as evidence of Greek and Egyptian cultures: a Roman brick wall dating from the Imperial age is still visible in the Palace cellars. In the sixth century the small church of Maria Sedes Sapientiae was built. In about 750 it was assigned by Pope Zacharias (741-752) first to the Basilians and later to other nuns until the Dominican period began in 1266.
In 1280 construction began on the new Gothic church of Santa Maria sopra Minerva and on the extensions to the adjoining convent. The convent was the venue of two conclaves which concluded with the proclamation of two humanist popes: Eugene IV (Gabriele Condulmer, 1431-1447) who made one of the first inventories of the Popes' library (350 Latin codices, as well as Greek and Hebrew codices) and Nicolò V (Tommaso Parentucelli di Sarzana, 1447-1455), a humanist and man of letters who encouraged the quest for manuscripts and illuminated codices throughout Europe and the East, including what was left of the Imperial Library of Constantinople after the Ottoman conquest (1453). The set of manuscripts and codices thus collected, including those of his own personal property, formed the nucleus of the Vatican Library, where one of the rooms bears his coat of arms and his name.
With the help of Oliviero Carafa, a theologian and jurist with a penchant for archaeology, the Cistern Cloister was added to the convent. In the cloister a sequence of frescoes (restored by the Chamber) in six lunettes depicts episodes from the life of Ste Catherine.
In 1563 Pope Pius IV chose the church of Santa Maria Sopra Minerva as the final destination of the solemn procession to celebrate the successful Council of Trent. The Dominican order took on increasing importance in Roman Catholic reform; this is why, in the latter part of the 16th century, when the order was ruled by Vincenzo Giustiniani, further buildings were added to the complex, in particular the "Bibliotheca", now the Capriate Room and the Refettorio adjoining the ancient kitchens.
In 1577 the Collegium Divi Thomae, the present-day Papal University of St Thomas, was built as a place of learning for poor, young Dominicans from the Italian provinces. On 14 September 1628, by papal decree, the monastery of Minerva was designated as the seat of the Congregation of the Holy Office. It thus became the place where the tribunal of the Inquisition, set up by Paul III in 1542, held the Secret Congregation meetings during which the sentences were read out. It was in a room of the Minerva Convent that on 22 June 1633 Galileo abjured the Copernican theory. In all probability the place chosen by the Congregation of the Holy Office consisted of the rooms now known as Galileo, embellished with frescoes by Francesco Allegrini, the most important of which represents a victory by the Catholic forces over the Albigenses in the battle of Muret in 1213.
IIn the late 17th century, Cardinal Girolamo Casanate, the Librarian of the Holy Roman Church, opened the Casanatense Library, which was independent of the convent library. At his death (1700) it was inherited by the Minerva Convent and was set up on the side of the building facing the large garden.
After the French occupation, which lasted from 1797 to 1814, during which time the convent, together with that of Sant'Agostino, was used as a barracks by two infantry regiments, the complex was returned to the Dominicans until 1871, when it was expropriated and used as the seat of the Finance and Treasury Ministry and subsequently of the Ministries of Education and the Postal System.
Ever since 1974 the complex has been used by the Chamber of Deputies which assigned the front part in Via del Seminario to the Bicameral Committees and the left side of the building, including the room used as the postal workers association theatre during fascism, to the Historical Archives. In 1989 also the Library was transferred from the fourth floor of Palazzo Montecitorio, no longer suitable for housing the hundreds of thousands of books, to its fully restored new site. Here it occupies the six floors of the right hand side (about 10,000 m2), thus allowing the ancient premises to be again used for cultural purposes.