Altar of Melitele

There are several altars in the game:
 * in St. Lebioda's Hospital. The hospital itself is in the Temple Quarter of Vizima.
 * in the swamp next to Vizima.

In St. Lebioda's Hospital, there is a novice nun praying by the altar, who can tell you about Melitele. She will also tell you that you can sacrifice fruits, plants or flowers on the altars. I could not sacrifice flowers like tulip, orchid, rose, etc; I could only sacrifice berries like grapes, blueberries, raspberries. The first sacrifice will give you three of the Sephirot: Ghe'vrath, Oth, Veen'ah. You will need these for the tower quest. After this, every subsequent sacrifices will give you an alchemical ingredient called Mistletoe.