Odnalazlem fragmenty zbroi Kruka, pancerz rodu Ruyter i zapiski elfiego mistrza piesni. Musze jeszcze odnalezc ostatni element.
Brakuje mi juz tylko litanii sw. Grzegorza.

The quest marker points to a Wayfarer's Stone. I gather I'm supposed to cast elemental spells at it, but does this message say which?

EDIT: I cast some spells at random and got to the next part of the quest, but a translation would still be appreciated.

"I've found a piece of the Raven's Armor, the cuirass of Ruyter lineage and the notes of Elvish Song Master. I have to find the last item: St. Gregor's litany"