Prague Castle Facts — History, Size & Key Details

Prague Castle is the most visited attraction in the Czech Republic, a UNESCO World Heritage Site, and the world’s largest ancient castle complex by verified measurement. It has been continuously occupied and used as a seat of power for over 1,100 years — longer than any other castle complex on earth. But beyond the headline records, the castle is full of specific, fascinating details that most visitors never hear unless they have a guide.

This article collects the most important and interesting facts about Prague Castle, covering size, history, architecture, legends, and current use.

Key Facts at a Glance

Size and Records

When most visitors picture a “castle,” they imagine a single large fortified building. Prague Castle is closer in scale to a small walled city — a complex of dozens of buildings representing nine centuries of construction, all within a continuous perimeter wall on a hilltop above the Vltava. Walking its full length from the First Courtyard in the west to the Na Opyši gate in the east takes approximately 20 minutes at a relaxed pace.

Founding and Early History

Prague Castle was founded around 880 AD by Prince Bořivoj, the first historically documented member of the Přemyslid dynasty — the ruling family that governed Bohemia for several centuries. Bořivoj moved his residence from Levý Hradec (north of Prague) to the strategic hilltop above the Vltava, where a Slavic settlement already existed.

The first walled structure was the Church of the Virgin Mary, some remains of which are still visible beneath the Second Courtyard in the form of archaeological excavations. The Basilica of St. George and a predecessor to St. Vitus Cathedral (a small rotunda) were both founded in the first half of the 10th century under Prince Wenceslaus I — the patron saint of Bohemia, canonised as St. Wenceslas.

The Přemyslids and Charles IV

The greatest period of construction was the 14th century under Emperor Charles IV (Karel IV), King of Bohemia and Holy Roman Emperor — arguably the most important ruler in Czech history. Charles IV rebuilt the Royal Palace, strengthened the fortifications, and — crucially — ordered the construction of the Gothic cathedral of St. Vitus in 1344 on the model of the great French Gothic cathedrals. St. Vitus Cathedral was begun under Charles IV but not completed until 1929 — a construction period of nearly 600 years.

Charles IV is buried in the royal crypt beneath St. Vitus Cathedral, along with other Bohemian kings.

The Defenestration of Prague (1618)

One of the most consequential events in European history occurred in a room at Prague Castle. On 23 May 1618, Protestant Czech nobles threw three Catholic officials — representatives of the Habsburg Emperor — out of a window of the Old Royal Palace’s Louis Wing. They fell approximately 17 metres and, according to historical records, survived by landing in a pile of horse manure (the Protestant account) or by the intervention of angels (the Catholic account).

This single act triggered the Bohemian Revolt and ultimately the Thirty Years’ War (1618–1648), which killed an estimated 8 million people across Europe. The room is still part of the Old Royal Palace circuit. Most visitors walk straight through it.

The word “defenestration” — throwing someone out of a window — entered the English language from this event. It was the third defenestration at Prague Castle (the first two were during the Hussite Wars in 1419 and 1483).

Rudolf II and the Alchemists

Emperor Rudolf II made Prague Castle his primary residence from 1583, transforming it into one of the great intellectual and artistic centres of Renaissance Europe. Rudolf was obsessed with alchemy, astronomy, and the occult. He employed some of the era’s most brilliant minds at the castle, including astronomers Tycho Brahe and Johannes Kepler, and numerous alchemists who worked in the castle’s laboratories.

The alchemists were reportedly given the use of the Golden Lane cottages (though historians debate whether they actually lived there or simply worked nearby). The name “Golden Lane” may derive from the goldsmiths who worked there, or ironically from its reputation as a poor street, or from the gold-seeking alchemists — sources disagree.

Rudolf II also assembled one of the greatest art collections of his era, displayed in the northern wing of the palace. Much of this collection was looted by Swedish forces during the Battle of Prague in 1648, which was the final act of the Thirty Years’ War.

A guided tour is the best way to hear the full Rudolf II story — guides can point to the specific rooms and tell the stories behind the alchemists, the astronomers, and the fate of the art collection.

The Crown Jewels

The Bohemian Crown Jewels — including the St. Wenceslas Crown, the royal orb and sceptre, the coronation cloak, and other regalia — are kept inside a hidden chamber within St. Vitus Cathedral. The chamber door has seven locks. Each of the seven keys is held by a different high-ranking official: the President of the Czech Republic, the Prime Minister, the Archbishop of Prague, the Chairman of the Senate, the Chairman of the Chamber of Deputies, the Mayor of Prague, and the Dean of St. Vitus Cathedral. All seven must be present simultaneously to open it.

The Crown Jewels are rarely displayed publicly. Viewings occur only on exceptional occasions and require authorisation by the President.

A legend holds that any usurper who places the Crown of St. Wenceslas on their head without authority is doomed to die within a year. Reinhard Heydrich, the Nazi Reich Protector of Bohemia and Moravia who used Prague Castle as his wartime headquarters, reportedly tried on the crown. He was assassinated by Czech paratroopers in 1942, less than a year later.

The Guards and Their Uniforms

Prague Castle is guarded 24 hours a day by the Castle Guard, an elite branch of the Czech military. The guard changes every hour from 7am to 8pm in summer at the Titans Gate (Hradčanské Square) and at the Powder Bridge Gate. The ceremonial Changing of the Guard with music, fanfare, and the changing of the Standard takes place every day at noon in the First Courtyard.

The guards’ distinctive uniforms — grey overcoats, white shirts, and black caps — were designed by Theodor Pištěk, an Oscar-winning Czech costume designer best known for his work on the 1984 film Amadeus.

Franz Kafka and Golden Lane

The writer Franz Kafka — one of the most important writers of the 20th century — briefly lived at No. 22 Golden Lane from November 1916 to March 1917. He rented the small blue cottage from his sister Ottla and wrote several of the short stories that would later be collected in the volume A Country Doctor. The cottage at No. 22 is one of the most photographed houses on the lane.

The Cathedral That Took 600 Years

St. Vitus Cathedral was begun in 1344 under Charles IV. Construction was interrupted by the Hussite Wars, resumed in the 15th century, stalled again, and was not completed until 28 September 1929 — nearly 585 years after it was started. The official completion ceremony on that date marked the thousandth anniversary of the death of St. Wenceslas, the cathedral’s patron saint.

The cathedral now contains the largest bell in the Czech Republic: the Sigismund Bell, weighing approximately 16.5 tonnes, cast in 1549.

Still an Active Seat of Government

Prague Castle is not merely a historic monument — it is the working office and official residence of the Czech President. Portions of the complex (including the presidential apartments, state rooms, and administrative offices) are not open to the public. State ceremonies, diplomatic receptions, and official visits take place here regularly, and the castle can close partially or fully on short notice when these occur.

The Czech President since 2023 is Petr Pavel.