Sierpc (Polish: [ɕɛrpt͡s]) is a town in north-central Poland, in the north-west part of the Masovian Voivodeship, about 125 km[2] northwest of Warsaw.

In 1831, after the unsuccessful Polish November Uprising against Russia, Sierpc was destroyed during military operations and a plague, but started to recover slowly.

It was then renamed to Sichelberg to remove traces of Polish origin The Germans established a prison for Poles in the town.

[8] Dozens of local disabled people were murdered by the Germans in March 1940 in the nearby Troska forest.

[9] On 5 April 1940 the Germans carried out mass arrests of about 600 Poles in the town and the county, who were then imprisoned in two local prisons.

[12] People were first deported to the Soldau concentration camp and afterwards to the General Government in the more eastern part of German-occupied Poland, while their houses and workshops were handed over to German colonists in accordance to the Lebensraum policy.

[16] It is an open-air museum and is located in the suburbs of Sierpc in the valley of the Sierpienica River and its confluence with the Skrwa Prawa.

Though it looks like a separate and independent village because of its great area (about 60.5 hectares) and because it is fenced, the museum is included within the town's borders.

The most valuable relic, not only of church but of the town are pieces of paintings from the Middle Ages and a sculpture from the 16th century "Generosity's Throne" made by the pupils of Veit Stoss.

The manor house was built at the turn of the 17th and 18th century and, undoubtedly, it is one of the most important monuments in the Sierpc area and the oldest architectonic laic object in the town.

There are plenty of mysterious legends and stories about "Kasztelanka" and the adjoining Benedictine monastery which is connected to it via a corridor.