 Sikorski's analysis of recovered chapter documents guided the Polish archaeological searches of Frombork in 2004–2005.The Institute of Anthropology and Archaeology at the Pultusk Academy of Humanities of Aleksander Gieysztor, with Polish archaeologists under the direction of , commenced the search for Copernicus’ grave from 16–31 of August, 2004, in an area of 10 square meters, and this search was financially supported by the Archaeologic Foundation of Prof Konrad Jażdżewski in Lódz, Poland.In the second archaeological search conducted in August 2005, Copernicus’ skull and remains were discovered in a grave marked by archaeologists as 13/5.