Shlisselburg or Oreshek fortress (Schlüsselburg in German, Noteburg in Swedish) stands on an island east of St. Petersburg. The small island Orekhovy (Russian for Nut) in the river Neva's outflow from Lake Ladoga is first mentioned in Novgorodian chronicles in 1228. It was part of Novgorod lands.

1323 To secure their lands and trade routes the Novgorodians build a wooden fort on the island. Orekhovy fort is burnt down during battles against Swedes in 1348.

1352 New stone defences are founded. At this stage Oreshek is a typical Novgorodian fort.

1471-1478 Novgorodian lands are incorporated into Muscovy. The development of firearms leads to modernizations in all Novgorodian forts. At the end of the XV century the old fortress is razed.

In XVI century the fortress covers the whole of Orekhovy Island. It has seven four-storey towers added to its walls. Inside, there's a three-storey citadel for further protection. The length of all walls put together is 740 metres, they are 12-15 metres high and up to 4,5 thick.

1612 during Livonian War Swedes overtake the fortress after a long siege. According to Stolbovo peace treaty in 1617 Sweden gains the Russian lands from the Gulf of Finland and Neva's shores. During The Great Northern War (1700-1721) these territories again fall into Russian hands.

1702 Russians regain control over Orekhovy Island. This is important as it means opening the way to Neva and the Baltic sea. Peter the Great starts to plan his new capital city, and Oreshek (now called Schlüsselburg, "The Key") is actively strengthened. First it is furnished with some earth walls, which then in 1740-1760 are gradually rebuilt in stone. By the middle of the XVIII century Peter's palace (Sovereign's House), Menshikov's palaces, Military barracks and Mint building (by architects Trezzini and Ustinov) have been erected inside the fortress.

Late XVIII century The island has now lost its strategic importance. The Church of John the Baptist by A.Vist and St John Cathedral by A.Schaubert are built. In 1812 the canons are sent off to St. Petersburg and the garrison is finally abolished.

From XVIII century and till 1917 Schlüsselburg functions as a political prison. New buildings are planned exclusively for this institution. The most famous prisoners include Eudoxia Lopukhina, the wife of Peter the Great, the young emperor Ivan Antonovich and some Decembrist rebels.

1941-43 the garrison of Schlüsselburg defends Neva's outflow and thus tries to keep the siege from closing up on the city.

In 1965 the badly damaged fortress was affiliated with The Historical Museum of Leningrad. The museum promptly launched extensive research work, archaeological studies included. According to the results of these efforts the fortress has also been restored and some defences reconstructed. The Sovereign's Tower, Golovin's Tower and Queen's Tower have so far been restored together with walls connecting them, the buildings of The Secret House (the XVIII century prison) and The New Prison dating back to the XIX century. The Cathedral and the walls belonging to XIV century Novgorodian fort have been conserved. The works on the fortress have slowed down lately due to the lack of funds.

In addition to the fortress itself there are some permanent exhibitions worth seeing. The fortress is open daily from 10 to 5 p.m. during the summer season. The ruins are accessible at tourists' own risk.