Castle in Olsztyn
Olsztyn Castle (Castle of the Warmian Cathedral Chapter)
The 14th-century Gothic castle where Nicolaus Copernicus lived, worked and left behind the only astronomical instrument of his that survives.
Reviewed and updated July 2026
What to see at Olsztyn Castle
Olsztyn Castle is a Brick Gothic stronghold raised between 1346 and 1353 for the Warmian Cathedral Chapter. Its best-known relic is an astronomical table that Copernicus drew directly onto a cloister wall in 1517 to track the equinox, described as the only surviving astronomical instrument he both made and used.
Copernicus at the Castle of the Warmian Cathedral Chapter
Copernicus administered chapter property from the castle between 1516 and 1521 and organised its defence during a Teutonic siege. The observations and calculations he carried out here fed into the heliocentric model he later published.
The Museum of Warmia and Mazury inside Olsztyn Castle
Today the castle holds the Museum of Warmia and Mazury, the regional museum for the Warmian-Masurian Voivodeship, with exhibitions across its Gothic halls. Check current opening hours and ticket prices on the museum's official channels before you visit.
Where Olsztyn Castle is
The castle stands at the edge of Olsztyn's Old Town beside the Lyna river, a short walk from the market square and the High Gate, so it pairs easily with a wider walk through the medieval centre.
Frequently asked questions
More to explore in Olsztyn
Nature
Masurian Lakes
A glacial maze of interconnected lakes and forest in the northeast, Poland's prime region for sailing, kayaking and slow summers on the water.
Attraction
Co-Cathedral Basilica of St James in Olsztyn
A red-brick Gothic hall church at the centre of Olsztyn's Old Town, raised for a Latin greeting.
Attraction
High Gate (Wysoka Brama)
The last of Olsztyn's three medieval gates and the most striking surviving piece of the old city walls.
Attraction
Olsztyn Old Town
A compact market square of gabled burgher houses, ringed by fragments of the medieval walls.
Attraction
Castle Park (Podzamcze Park)
A landscaped riverside park below Olsztyn's Warmian Chapter Castle, set on the site of former water mills and revitalised in the late 2010s, near the neighbouring Central Park.
Restaurant
Restauracja Przystan
A large two-level restaurant built out over the docks of Lake Ukiel, leaning on regional and freshwater dishes.