At its core, this is a Gothic house, documented around the mid-15th century under the name At the Stone Lamb, and it is decorated mainly with a grand early Renaissance portal with a balcony dated to c. 1531. The portal is connected to the activity of the circle of masons connected to the court of Benedikt Ried. Above the portal is a stone slab with a somewhat mysterious house sign depicting an animal which resembles a lamb with only one horn, and a virgin standing next to it. The mason who worked on the slab in c. 1530 might have reworked an already existing sign with a lamb to present a unicorn. The house is mentioned in archival sources under the name At the White Unicorn from the mid 16th century, a pharmacy was located there from 1778 to 1945. Apart from the portal the facade of the house has been preserved in its Neo-Classical form. The commemorative plaque on the house mentions the fact that Albert Einstein used to play violin there in the salon of Berta Fantová between 1911 and 1912 and would meet with his friends Franz Kafka and Max Brod there. At the time Einstein was a professor of theoretical physics at the university in Prague. However, the truth is that Berta Fantová had her salon in the neighbouring house At the Stone Table.
Like the neighbouring Štorch's house, the house At the Stone Lamb was hit by German shelling aimed at the Old Town centre with the town hall. The south front of the square was one of the most damaged areas due to the repeated attacks from Letná and Pařížská Street. Except for the facade, the house At the Stone Lamb was completely destroyed by fire and had to be rebuilt after the war.