The enormous Hofburg complex differs from other large royal palaces in that it does not consist of a single building commissioned by a monarch to an architect. Contrary to what we are used to in terms of palace architecture, over a period of more than six centuries the various rulers who resided here extended the original structure to the point where it consisted of a dozen buildings.

In fact, after the various additions, the Hofburg may appear more like a city within a city, occupying as it does, an impressive area of 240,000 square metres divided into 18 wings, 19 courtyards and 2600 rooms. The various buildings reveal an architectural evolution that extends from Gothic to Historicism. However, the whole is dominated by Baroque and Neoclassical elements.

To explore the history of the Hofburg Palace is to step into the history of Austria and the Habsburg dynasty that came to rule half of Europe from here in their capacity as leaders of the Holy Roman Empire of the German Nation and later the Austro-Hungarian Empire. 

The oldest part of the Hofburg, which was once called the Alte Burg and is now known by the name Schweizertrakt, or The Swiss Wing, dates from the 13th century and was originally a fortified structure consisting of four defence towers, a moat and a drawbridge, before undergoing modifications on several occasions.

In this wing of the palace, which was renovated in Renaissance style in the 16th century, one can visit the spectacular Schatzkammer, or Treasuries, which, by means of the fabulous jewels on display, including valuable symbols of power such as crowns and sceptres, reveals a fundamental part of the history of the Habsburgs.

The year 1449 saw the construction of the Burgkapelle, the palace chapel in which the Wiener Sängerknaben, or Vienna Boys' Choir, performs every Sunday.

By the mid-16th century construction had begun on a new part of the building, the Stallburg, which was eventually refurbished and since the 18th century has housed the stables for the horses of the beautiful Spanische Reitschule, the Spanish Riding School.

In the same century work began on a separate building, opposite the Schweizertrakt. This structure is now known by the name Amalienburg. Erected as a residence for Rudolf, son of the Emperor Maximilian, the name is derived from the Empress Amalia Guillermina, who resided here after the death of her husband, Emperor Franz Joseph I. 

The building is also renowned for the last person to reside here, none other than Empress Sissi. Today, the rooms form part of one of the guided tours that can be taken of the palace.

Between 1668 and 1680, by order of Leopold I, the Amalienburg wing was connected to the Schweizertrakt, the Baroque wing connecting the two buildings receiving the name Leopoldinischer Trakt. Today this part of the complex perpetuates the role of the Hofburg as a centre of power, the offices of the President of the Republic of Austria having been housed here since 1946.

During the 18th century the great architect Johann Bernard Ficher von Erlach added a series of gems to the palace, such as the Prunksaal, the beautiful Baroque building that originally housed the valuable volumes belonging to the Habsburgs' library. Built between 1723 and 1735, it is now the flagship of the Österreichische Nationalbibliothek, the National Library of Austria. 

Another achievement of Fischer von Erlach was the Reichskanzleitrakt, the wing of the Imperial Chancellery, which was completed circa 1730. Following the dissolution of the Holy Roman Empire of the German Nation, this building, originally used as the chancellery for said empire, was converted into residences for members of the imperial court. Possibly its most famous tenants were Empress Sissi and Emperor Franz Joseph, who lived in the Reichskanzleitrakt during the second half of the 19th century. 

This part of the Hofburg, which is accessed through the gates known as Kaiserstor, is one of the biggest attractions on the palace tour, which also includes access to the Sissi Museum, which focusses on the figure of the mythical Empress, and the Silberkammer, the suite of rooms in which the luxurious dinnerware, tableware, tablecloths and cutlery used by the Habsburgs are displayed. Luxurious pieces of gold, silver, porcelain... From China, France, Italy... Highlights among the most beautiful pieces found here include the monumental Milan centrepiece, a gilded bronze set which, when combined, reaches 30 metres in length and is displayed here in all its finery.

In addition to the Winterreitschule, the building designed and built for the Spanish Riding School by Fischer von Erlach between 1729 and 1735 by order of Charles VI, there is the Redoutensäle, a series of halls designed during the 18th century for the celebration of dances. 

The most significant construction carried out here during the 19th century corresponds to the Michaelertrakt, the curved wing, which is crowned by an imposing 50-metre dome and which faces the Innere Stadt. Its architect was Ferdinand Kirschner. 

The final section of the palace, the neo-Renaissance wing of the Neue Burg, was completed in 1913. With its curved façade overlooking Heldenplatz, it was part of an ambitious project to erect an imperial forum. The project was designed by architects Gottfried Semper and Karl von Hasenauer but never materialized beyond the building of the Kunsthistorisches Museum and the Naturhistorisches Museum, which are located on the other side of the Ringstrasse. 

Today, this part of the building has an interesting function, as it hosts several collections of the National Library of Austria in addition to other cultural institutions such as the Ephesus Museum and the Museum of Ethnography. 

With all its majesty, beautiful forms and prodigious dimensions, the constant additions to the Hofburg are a reflection of the power of the Habsburgs who, over the course of several centuries, constructed a great empire into which other nations were continually absorbed. Fortunately for lovers of art and architecture, and unlike the Austro-Hungarian Empire, which collapsed after the First World War, the palace remains proudly intact despite its centuries of history. 

The imperial residencies, the Sissi museum and the Silberkammer all offer interesting guided tours, and free audio and texts in eleven languages covering the most important details of the complex are available from the museum's website.