Most of the inhabitants continued heathens until, according to the legend, Salsa, a Christian maiden, threw the head of their serpent idol into the sea, whereupon the enraged populace stoned her to death.
Once more, Gregory is remembered as a great organizer of missionary enterprise for the conversion of heathens and heretics.
Here Christian, bishop of Prussia, who had received from the Polish duke of Masovia a part of Kulmerland as a fief, had founded the knightly Order of Dobrzin, and was attempting with its aid to subdue the heathens of Prussia.
In 1748 he published some Remarks on an Enquiry into the Rejection of Christian Miracles by the Heathens (1746), by William Weston, a fellow of St John's College, Cambridge.
The first part of the Instructiones is addressed to the heathens and Jews, and ridicules the divinities of classical mythology; the second contains reflections on Antichrist, the end of the world, the Resurrection, and advice to Christians, penitents and the clergy.
With eighteen companions he set out; but on the borders of the Russian (Lithuanian) country he and all his company were massacred by the heathens (February 14, 1009).