 The remains were genetically tested in Poland and Sweden and found to match hair samples taken from a book owned by Copernicus which was kept at the library of the University of Uppsala in Sweden.Sikorski discovered the location of Copernicus' Canonic Curia outside the walls of Frombork (the "Curiae extra muros").The building is not extant, having been burned by Teutonic Knights on February 1, 1520, but the foundation remains.