According to the will, the heart extracted from Kosciuszko's body was placed in an urn and given to Emilia Zeltner, the daughter of Franz.

In 1819, Emilia took the urn containing Kosciuszko's heart to Vezia near Lugano and in 1829 to Varese, Italy. Finally, in 1895, the urn was donated to the museum in Rapperswil, where it was decided to place it in the local church of St. John the Baptist.