Behind the discreet classical façade lies a true pearl of architectural art — authentic interiors that amaze with their luxury and splendor. Unique decor made of the most valuable wood and marble, parquet flooring and moldings, as well as much more that can amaze the imagination of the most discerning visitor to this wonderful place have been preserved to this day. During its existence, the mansion changed many owners. In 1835, the house was bought by Prince Sergei Sergeevich Gagarin. At his request, the architect A. H. Pel built a front wing on Bolshaya Morskaya Street (house No. 52), which has been preserved here to this day.

In 1864, Prince Gagarin's son sold the house to the wife of State Councilor Alexander Alexandrovich Polovtsev, Nadezhda Mikhailovna. The mansion was purchased with money from Nadezhda Mikhailovna's adoptive parents — the family of the banker Stieglitz. There were rumors that she was the illegitimate daughter of Grand Duke Mikhail Pavlovich.

For the Polovtsev family, magnificent ceremonial interiors were created in the mansion, most of which can be seen today. G. A. Bosse, N. F. Bryullo, M. E. Mesmakher worked on the interiors.

In 1930, a trade union school was opened in the Polovtsev mansion, later transformed into the Higher Professional School of Culture. Since 1934, the Polovtsev mansion has housed the St. Petersburg branch of the Union of Architects of Russia. Since then, the mansion has also been called the House of the Architect.