The Church of Saint Thyrsus (Iglesia de San Tirso) was established in the 790s. Dedicated to Saint Thyrsus, it was built by Tioda, the royal architect of Alfonso II of Asturias. The Great Fire of Oviedo in 1521 and rebuilding in the 18th century removed most of the original church, except for a three-light window.
The building has suffered so much from alterations over the centuries and only the general plan has been preserved. It is that of a basilica with nave and aisles divided by rude stone piers set at unequal intervals, from which round arches spring. In the easternmost bay, however, owing to the smaller span, the arch was made sufficiently pointed to raise its crown to the same height as the others. This irregularity was already typical of Imperial Roman times, when barrel vaults were given a pointed form in order to make the height of rooms of varying size uniform, as it was necessary to raise the crown of the vault in some of them. This is illustrated by various chambers in the House of Tiberius on the Palatine.
There is no satisfactory explanation of the 'many angels' the building is said to have presented in the Codex Vigilianus.
In the rectangular sanctuary atriplet round-arched window 2 by 2 metres is preserved. With its pre-romanesque bases, rough brick arches, and capitals with rude packed leaves, it gives an idea of the better style of building and carving in the time of Alfonso II of Asturias. It is known that the church of San Tirso housed Royal Chapel.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.