Building complex of Loreto was constructed mainly at the financial expenses of the Lobkowitz family. Central part, not only the building one, but mainly the ideological one, called Holy Hut, rose during 1626-1631 under command of Giovanni Battiste Orsi. Then ambits with bay chapels were built there progressively pursuant to design by the same architect. About 1740 the top floor was built on. On the place of an older chapel, in the middle of the eastern ambit Church of the Nativity of Our Lord was built during 1734-1737, under command of builder Jan Jiří Aichbauer. In the courtyard there are two fountains with sculptural groups of Raising of Christ and the Assumption of the Virgin Mary by sculptor Jana Brüderle from 1740.
Main Loreto building, which forms the front into the Loreto Square, has undergone several reconstructions. The main front, which is nearly 55 m long, got its final form by Kilián Ignác Dientzenhofer. The building had been enriched with three high gables, which got attic and numerous sculptural decorations. Front tower, which is prismatic at the bottom, changes into an octagon with pointed windows in the upper part, in which Loreto peal of bells is hung on oak beams. It was consecrated in 1695. The tower is ended with an imperial dome with a lantern and a balloon. At sides of the main entry, where an alliance coat-of-arms of the Loreto patron is, there are sculptures of St Anthony and St Francis. At the entry to a balcony above the main porch there are sculptures of St Joseph and St John the Baptist. On the attica there are sculptures of the Evangelists, Matthew, Mark, Luke, John and sculptures of St Christopher carrying the Christ Child and St Anne. Front of Loreto is separated from area of the square by a fore-yard, fenced by a stone balustrade with figures of angels. Around 1683 a treasure house rose with world-famous Loreto treasure in the front building.
Premises of Loreto, together with the Czernin Palace, Franciscan cloister and Church of the Virgin Mary and St Angels forms an outstanding urban complex of the Loreto Square.