This early account was further enhanced by Simon Grunau in the 16th century. He described an eternal sacred fire, an eternally green oak with idols representing a pagan "trinity": Patrimpas (god of spring), Perkūnas (god of thunder) and Patulas (god of the underworld). The place was guarded by priests and vestales. Images appeared based on this description and became very popular with romantic historians. Grunau changed the name for the place to Rickoyoto (from Prussian "rikijs" - ruler and "-ote" - a place name ending) and invented the term "Kriwe of Kriwes" (Lithuanian: "krivių krivaitis", Latvian: "krīvu krīvs").