Zamek Książąt Mazowieckich w Ciechanowie

Ciechanów, Poland, Poland

---

Zamek Książąt Mazowieckich w Ciechanowie, located in Ciechanów, Poland, is a well-preserved Gothic brick castle built at the turn of the 14th and 15th centuries by Duke Siemowit III around 1370 and expanded by his son Janusz I after 1410 into a grand residence on a rectangular 48x57m plan with corner towers and a large internal courtyard.

Positioned in a marshy bend of the Łydynia River for defense, it featured initial walls about 5m high, later raised, and served as a refuge during Lithuanian and Teutonic invasions while evolving from fortress to royal seat through 16th-century reconstructions.

Damaged by fire in 1467 and Swedish forces in the 17th-century Deluge, it fell into partial ruin by the late 1700s under Prussian control but now stands as a major museum and heritage site showcasing Mazovian ducal history.