Frombork castle and cathedral were built by the Teutonic knights in the 14th century.  In 1466, Frombork became a part of Poland and during the years 1512-1516 and 1522-1543 the castle was the workplace of the astronomer Nicholas Copernicus.  Before his death at Frombork, Copernicus published his heliocentric theory of the solar system.  This theory superseded Greek astronomy and started what is sometimes called the Copernican revolution and slowly gave rise to modern science.
   Unfortunately, the town of Frombork suffered 70% damage during the Second World War and was later reconstructed.

    Frombork castle consists of only an enclosing wall, a few simple buildings and the above Gothic tower, originally constructed during the second half of the 14th century.  According to legend, Copernicus used the tower to make observations about the movements of celestial bodies.