The elaborate stone portal is filled with messages of duality and transformation

On Old Town Square, there is a house with a plaque saying Albert Einstein used to stop by there. But the house is quite old and has another claim to fame.

The house gets its name from a strange depiction of a shepherdess and a horned stone lamb, which is sometimes called a unicorn. The house is known as At the Stone Lamb or At the Unicorn, depending on whom you ask.

The house is thought to be where Tadeáš Hájek z Hájku lived. He was an astrologer and personal physician to Emperor Rudolf II, but one of his main duties seems to have been vetting the alchemists that came to Prague from all across Europe.

House at the Stone Lamb

Entry portal to the House at the Stone Lamb

The Royal Route leads from the Powder Tower on náměstí Republiky, goes down Celetná Street to Old Town Square, then down Karlova Street, across Charles Bridge and up Nerudova Street to Prague Castle.

The house is placed near the start of what could be a long journey.

Prospective alchemists who hoped to eventually meet the Emperor would first stay at a hotel on Celetná Street, waiting for a chance to show their skills to Tadeáš Hájek. The building that was the hotel back then is still a hotel, and above the entry it has a sculpture of a golden angel with a staff of Mercury and a cornucopia.

Other traces of alchemy can be found all along the Royal Route, and the House at the Stone Lamb is perhaps the best example.

House at the Stone Lamb

Left side of the entry to House at the Stone Lamb

The ornately carved stone entry is covered in mystical symbols that have alchemical interpretations. On the capital of the pillar on the left, as you look at it, has a side-by-side crescent moon and a sun, both with human faces. The sun and moon are bound together where they meet by the image of four bands of a rope. They are surrounded by oak leaves, flowers, fruit and what looks like three round bells.

The capital on the right side is different. Its centerpiece is a fool’s face in a crescent-shaped hat in a circle next to a hedgehog or pig in a barrel, also in a circle. Above the circles there are again three bells, but this time thorn branches, five-petaled flowers and berries, possibly representing raspberries or grapes.

House of the Stone Lamb

Right side of the entry at the House of the Stone Lamb

The sides of the capitals, a bit hard to see, have additional images such as a male figure riding a sow, two boys playing, a woman working at a table, cryptic circular designs, a six-pointed star, hops and potted flowers.

The sun and moon can be can be interpreted as gold and silver, and also as active and passive, constant versus shifting and so on, There are dozens of meanings. Joining opposing forces is one of the goals of alchemy.

The fool and hedgehog are a bit more cryptic. The fool can be a beginning scholar or a stand-in for Mercury. The fool is also an observer who had special privileges at court. The hedgehog in barrel is a bit odd, but contrasts with the outgoing nature of the fool.

Side of the left capital

Side of the left capital

Both the sun and fool have been suggested as symbols of sulfur, while the moon and hedgehog have been linked to the element mercury.

Hops are of course associated with beer. Oak is a symbol of sacred wisdom to many people, as the trees stand for a long time and withstand the forces of history.

The shafts of the both columns looks very modern. Lines create an elongated X, a sign of transformation. The lines on the bottom merge in the center and break out again, separate but different.

Side of the right capital

Side of the right capital

The entablature, or stone beam across the top of the entry, disappointingly is lacking in design.

The house sign, which gives the building its name, is a cause of some dispute. Some people favor calling it a lamb that inexplicably has a single horn. Others consider it a unicorn, an animal associated with innocence, purity and feminine energy.

People in the middle ages considered unicorns to be real. Foreign merchants would pass off horns of various Asian, African or ocean animals as unicorn horns, and chalices made of unicorn horns can be found in some castle collections.

While it was often depicted as a horse with a horn, there were many variations as nobody had ever seen one.


The house at Staroměstské nám. 551/17 is not open to the public, save for some small tourist shops on the ground level. The building houses law offices, a municipal institute that oversees funeral services, and some private flats.

When Albert Einstein lived in Prague from 1911–12, he used to visit the salon of Berta Fanta, who was a supporter of artists in the German-speaking Jewish community. Franz Kafka and Max Brod were also among the visitors. Allegedly on one evening, Einstein played the violin, along with a pianist, while Kafka read from his unpublished works.

Plaque for Albert Einstein

Plaque for Albert Einstein

The building was originally made in the Gothic style, and has been on the square since at least the 14th century. The building was damaged by fire in the last days of World War II, and has been heavily repaired.

The stone entry with the alchemical designs dates to around 1520, about half a century before Emperor Rudolf II became King of Bohemia in 1575. So its alchemical symbols even predate the fad for the art that flourished in Rudolf’s time.

The stone carving is sometimes attributed to architect Benedikt Rejt (or Rieth or Reyd). He worked on parts of Prague Castle including the Ladislav Hall and on churches such as St. Barbara’s Church in Kutná Hora.

House at the Stone Lamb

Tourists watch a street performer in front of the House at the Stone Lamb

The Renaissance gable dates from the 17th century.

The house carried on its connections to alchemy as it held a pharmacy on its entry level from 1778 until the fire in 1945. It was known in the 19th century for its special recipe for sleeping pills.

The name House at the Stone Lamb (Dům U Kamenného beránka) is preferred to House at the Unicorn (Dům U jednorožce) by some people because there are several other houses associated with unicorns in the Old Town Square area, and it causes confusion, with people looking in vain for mystical symbols or Einstein’s plaque at the wrong place.

Tadeáš Hájek z Hájku, also known as Thaddaeus Hagecius ab Hayek or Thaddeus Nemicus, was a Czech naturalist, astronomer, personal physician of the Holy Roman Emperor Rudolph II. He lived Dec. 1, 1525, to Sept 1, 1600.

Engraving of Tadeáš Hájek

Engraving of Tadeáš Hájek. Public domain

He was made knight of the Holy Roman Empire by Rudolf II, after also receiving honors from Ferdinand I of Germany and Maximilian II.

He studied medicine / alchemy and astronomy / astrology in Vienna, Bologna and Milan. He taught mathematics at Charles University from 1555. He published a book in 1561 dealing with reading lines on the forehead to tell the future, and made a triangulated map of of Prague in 1563, now lost.

From 1564 onward by the Emperor’s order, no astrological forecast or horoscope could be printed in Prague unless Hájek approved it.

Etching of Tycho Brahe

1586 portrait of Tycho Brahe with the coats of arms of his noble ancestors, by Jacques de Gheyn. Public domain

He wrote about the 1572 supernova in Cassiopeia and kept up a correspondence with Tycho Brahe. Hájek helped to convince Rudolph II to invite Brahe and Johannes Kepler to Prague. He also corresponded with John Dee about Euclidean geometry.

Hájek’s Czech-language horoscopes and predictions are why he is remembered more as an alchemist and astrologer than as a serious scientist but in his lifetime there was no distinction between the two.

His astronomical writings in Latin show he was one of the most significant astronomers of his time. A lunar crater and an asteroid are named after him.

An article by Baba Studio with Raymond Johnston. Copyright Baba Studio, all rights reserved. Please contact us if you would like to syndicate or otherwise use this article.

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