Two parts of the Peter and Paul Fortress were used as prisons. Initially, it was the Trubetskoy Bastion. In the first quarter of the 18th century, the casemates of the Trubetskoy Bastion were used as detention cells by the Secret Chancellery. In 1718, the son of Peter I, Tsarevich Alexei Petrovich, accused of participating in a state conspiracy, was held here, where he died (or was executed) on July 7, 1718.

Later, the prison was moved to the Alekseevsky Ravelin. Its history is inseparably linked with that of the Trubetskoy Bastion. This western fortification of the Peter and Paul Fortress was laid by Empress Anna Ioannovna on July 1, 1733, in honor of Tsar Alexei Mikhailovich. The auxiliary triangular-shaped structure in front of the fortress moat served to cover the Vasilievskaya Curtain and its gates.

As early as 1769, a wooden prison was built in the ravelin, which in 1797 was replaced by a stone prison with 20 cells — the "Secret House." In 1796, Emperor Paul I ordered: "For those held in custody on cases related to the Secret Expedition, to construct a House with conveniences for detention within the fortress." The estimate for the stone building and the "Inventory of items of the new state house in the Alekseevsky Ravelin" confirm that this refers to the "Secret House," which functioned as a prison until 1884. Among the ravelin's prisoners were Decembrists, Petrashevtsy, and Narodniks (until 1884; many of the latter died during solitary confinement in 1882–1884).

However, in 1884, the prisoners were transferred to the Shlisselburg Fortress, after which the Alekseevsky Ravelin was no longer used as a prison.

In 1895, the prison of the Alekseevsky Ravelin was demolished, and the Neva channel that created the island was filled in with earth.

The second facility was the new prison of the Trubetskoy Bastion, which existed from 1872 until 1921. The prison was built between 1870 and 1872 according to the designs of engineers K. P. Andreev and M. A. Pasyupkin. The two-story, pentagonal building was erected on the site of the dismantled internal walls of the Trubetskoy Bastion. Initially, the prison had 73 solitary cells, but from 1878 the number was reduced to 69. This prison was the main investigative prison for those accused of political crimes. A strict system of solitary confinement was established here, aimed at complete isolation of the prisoner from the outside world and other detainees. The prison was guarded by the only special Observation Team in the country, and from 1880, a team of gendarme observers was added.

Between 1880 and 1884, political prisoners sentenced to hard labor were also held in the Trubetskoy Bastion, where an exceptionally harsh regime was created for them (ban on using books — initially only the Gospel was issued, later the Bible — smoking, visits, correspondence; beds had to consist of felt instead of a mattress and a pillow stuffed with straw).

On February 3, 1879, a riot broke out in the prison due to the refusal to grant tobacco to one of the prisoners. The inmates demanded an improvement in conditions and, when their demands were not met, expressed their protest by banging, beating on doors, and breaking furniture. They were tied up and beaten by soldiers. A hunger strike followed, lasting several days. As a result, the prisoners' demands were partially met.

Among the famous inmates were Kropotkin, Zhelyabov, Ulyanov, Vetrova, Savinkov, Breshko-Breshkovskaya, Chernov, Bauman, Gorky, Trotsky, Parvus, and many others.

https://foto-history.livejournal.com/13094931.html

https://ru.wikipedia.org/wiki/Trubetskoy_Bastion_Prison

https://spb.aif.ru/society/people/vnutri_sekretnogo_doma_kak_byla_ustroena_tyurma_v_alekseevskom_raveline