The Holy Trinity Church was built in the years 1694–1702. Authority of the church and the seminary was the founder Prince Archbishop Johann Ernst von Thun. The church, together with the same time build St. John's Church (hospital church) the first building designed by Johann Bernhard Fischer von Erlach in Salzburg. He used as models various religious buildings in Rome—especially Francesco Borromini's Church Sant'Agnese in Agone in Piazza Navona. While the church is characterized by a discreet use of decorative elements, the entire structure conveys a palatial impression.
The church interior is a longitudinal oval room with four short barrel vaults with crossed arms, which are surmounted by the large drum dome. The monumental effect of the interior arises mainly from the simplicity of the building and the towering height of the dominant drum dome. The design is reminiscent of the inner shape of the Karlskirche in Vienna, which was the second sacral masterpiece by Fischer von Erlach.
The large dome fresco inside the church, Coronation of the Virgin, was executed by Johann Michael Rottmayr between 1697 and 1700. It was Rottmayr's first sacral dome fresco and shows the Coronation of the Virgin by the Holy Trinity with the assistance of the Archangel Michael, as well as other saints, angels, prophets, the ten holy popes, and the Church patriarch. The fresco sums up the Christian salvation and church history impressively together. The figures are grouped in concentrically arranged cloud banks. At the top lantern a Holy Spirit dove is present. The large dome fresco completes the impression of Baroque ecclesia triumphans, the triumphant Church, within the meaning of Baroque self-understanding of the church building.
The stucco work by Andrea Sallari and Johann Baptist Redi is limited in the main room to the capitals, and in the cross arms stucco boxes. The high altar was created in 1700 according to plans by Fischer von Erlach. It was revised in 1841, but was returned to its original state in 1947. The altar contains a sculptural group of the Trinity group with two adoring angels. The reliquary of St. Ernestus was designed in 1959 by Otto Prossinger. The two side altars contain magnificent life-size angels, which were designed by Fischer von Erlach and Michael Bernhard Mandl from 1700–02. The Marie miraculous image of the right side altar dates from the sixteenth century. The Baroque frame was carried out by Sebastian Stumpfegger.References:
Thank you Richard for comments and detailed information. The overall photo was incorrect as you mentioned and is changed now.
The overall photograph is not of the Holy Trinity Church, but rather of the Salzburg Cathedral [Dom zu Salzburg] about 1/3 mile south-ish across the Salzach. Its based on an original design by Vincenzo Scamozzi and implemented by Santino Solari. The project was complete by 1628, nearly 70 years before the Holy Trinity Church; and the two represent very different interpretations of Baroque architecture. The Cathedral is much more reminiscent of Palladio in its clearer geometry and combining of solid forms, evident both from the interior and exterior. The Holy Trinity is much more reminiscent of Borromini, which can be understood primarily from its interior.
Steinvikholm Castle is an island fortress built between 1525 to 1532 by Norway's last Catholic archbishop, Olav Engelbrektsson. Steinvikholm castle became the most powerful fortification by the time it was built, and it is the largest construction raised in the Norwegian Middle Ages.
The castle occupies about half of the land on the rocky island. The absence of a spring meant that fresh water had to be brought from the mainland. A wooden bridge served as the only way to the island other than boat. Although the castle design was common across Europe in 1525, its medieval design was becoming obsolete because of the improved siege firepower offered by gunpowder and cannons.
The castle was constructed after Olav Engelbrektsson returned from a meeting with the Pope in Rome, presumably in anticipation of impending military-religious conflict. As Archbishop Engelbrektsson's resistance to the encroachment of Danish rule escalated, first with Frederick I of Denmark and his successor Christian III of Denmark, Steinvikholm Castle and Nidarholm Abbey became the Catholic Church's military strongholds in Norway. In April 1537, the Danish-Norwegian Reformation succeeded in driving the archbishop from the castle into exile in Lier in the Netherlands (now in Belgium), where he died on 7 February 1538. At the castle the archbishop left behind St. Olav's shrine and other treasures from Nidaros Cathedral (Trondheim). The original coffin containing St. Olav's body remained at Steinvikholm until it was returned to Nidaros Cathedral in 1564. Since 1568 St. Olav's grave in Nidaros has been unknown.
From the 17th to 19th century, the island was used as a quarry and some of its masonry was sold and removed from the site. This activity was condoned by the Danish-Norwegian authorities as a way of eliminating a monument to the opposition of the Danish–Norwegian Union.
Steinvikholm fort is owned and operated today by The society for the Preservation of Norwegian Ancient Monuments. The island has been the site of the midnight opera which details the life and struggles of the archbishop. The opera is held in August annually. The opera is organized by Steinvikholm Musikkteater since the beginning in 1993.