The castle was built in the 12th century to guard the road from Chur over the alpine passes. The oldest part of the castle, the ring wall, was built in the second half of the 12th century. The main tower was added in the early 13th century. The Lords of Strassberg first appear in the historical record in 1253.
The ring wall around the main castle originally had a residential building along the north side and still shows signs of windows and privies. In the 13th century a large, square, four-story tower was added on the west side of the ring wall. East of the main ring wall was another, larger ring wall which may have included a gate house. Very little of this outer wall remains and it is unclear how it connected to the main castle.
The castle is first mentioned in a record in 1275 as castrum dictum Strasceberch and at that time it was owned by the powerful Freiherr von Vaz. The Strassberg family appear to have been ministerialis, unfree knights in service to a higher noble, or vassals of the Vaz family. Strassberg castle allowed the Vaz to collect taxes from trade along the road. In addition, it protected nearby Churwalden Abbey, which was the burial place of the family. After the extinction of the Vaz family, in 1339, the castle was inherited by the Counts of Toggenburg.
The Toggenburg counts received imperial permission to establish a customs station at Strassberg in April 1348. However, the Bishop of Chur objected and by December of the same year, the Toggenburg permission was revoked. Over sixty years later, in 1413, they were able to acquire customs rights from Emperor Sigismund, which when the bishop objected, ended up with Zürich having to arbitrate between the Toggenburgs and the bishop.
In 1360 the last Strassberg died out and the castle passed fully to the Toggenburgs. For the next three quarters of a century several different Toggenburg vassals held Strassberg as a fief. When the last Toggenberg count, Frederick VII, died the castle was inherited by the Counts of Montfort. Probably due to the power of the League of the Ten Jurisdictions Monfort granted the town of Churwalden its freedom and a promise that the castle would always stand open to Churwalden and that the vogt would only live in the castle if the town granted its permission. In 1466 the Counts of Montfort sold the castle to Archduke Sigismund of Austria. A few years later, in 1471 Sigismund sold the castle to Ulrich von Matsch and then inherited it back in 1479.
The castle began to fall into ruin and in 1491 Vogt Disch Ammann von Rhäzüns reported that the castle was somewhat damaged. On 5 March 1499, during the Swabian War, the castle was burned by retreating League troops to prevent it from falling into Austrian hands. By the 16th century it was already a ruin.References:
Royal Palace of Naples was one of the four residences near Naples used by the Bourbon Kings during their rule of the Kingdom of the Two Sicilies (1734-1860): the others were the palaces of Caserta, Capodimonte overlooking Naples, and the third Portici, on the slopes of Vesuvius.
Construction on the present building was begun in the 17th century by the architect Domenico Fontana. Intended to house the King Philip III of Spain on a visit never fulfilled to this part of his kingdom, instead it initially housed the Viceroy Fernando Ruiz de Castro, count of Lemos. By 1616, the facade had been completed, and by 1620, the interior was frescoed by Battistello Caracciolo, Giovanni Balducci, and Belisario Corenzio. The decoration of the Royal Chapel of Assumption was not completed until 1644 by Antonio Picchiatti.
In 1734, with the arrival of Charles III of Spain to Naples, the palace became the royal residence of the Bourbons. On the occasion of his marriage to Maria Amalia of Saxony in 1738, Francesco De Mura and Domenico Antonio Vaccaro helped remodel the interior. Further modernization took place under Ferdinand I of the Two Sicilies. In 1768, on the occasion of his marriage to Maria Carolina of Austria, under the direction of Ferdinando Fuga, the great hall was rebuilt and the court theater added. During the second half of the 18th century, a 'new wing' was added, which in 1927 became the Vittorio Emanuele III National Library. By the 18th century, the royal residence was moved to Reggia of Caserta, as that inland town was more defensible from naval assault, as well as more distant from the often-rebellious populace of Naples.
During the Napoleonic occupation the palace was enriched by Joachim Murat and his wife, Caroline Bonaparte, with Neoclassic decorations and furnishings. However, a fire in 1837 damaged many rooms, and required restoration from 1838 to 1858 under the direction of Gaetano Genovese. Further additions of a Party Wing and a Belvedere were made in this period. At the corner of the palace with San Carlo Theatre, a new facade was created that obscured the viceroyal palace of Pedro de Toledo.
In 1922, it was decided to transfer here the contents of the National Library. The transfer of library collections was made by 1925.
The library suffered from bombing during World War II and the subsequent military occupation of the building caused serious damage. Today, the palace and adjacent grounds house the famous Teatro San Carlo, the smaller Teatrino di Corte (recently restored), the Biblioteca Nazionale Vittorio Emanuele III, a museum, and offices, including those of the regional tourist board.