This sundial, created ca. 1490 on the south side of Cathedral Basilica, is one of the oldest in Europe.
It is supposedly made by Nicolaus Copernicus (Mikolaj Kopernik) together with his teacher, an astronomer Mikolaj Wodka.
When Nicolaus Copernicus was 15 he was sent to the cathedral school in Wloclawek, where in 1488-91 he would be prepared for his higher studies. One of his teachers was Dr. Nicolaus Wodka (Abstemius), a scientist graduate of University of Krakow and University in Bologna. He was a specialist in gnomonics, the study of shadows cast by gnomon, the pointer on a sundial. Nicolaus probably studied astronomy with him and they might have constructed the Cathedral sundial together.
This sun watch is unique for the 15th century, as it shows not only the time, but also the actual Zodiac sign as well as how many hours of daytime brightness contains any day of the year.
On the top there is also a poem, writen in Latin by Nicolaus Copernicus.