The people know a strange legend of the Sibyl. Sybylla or the Sibylle is known to them as a great prophetess who is doing penance in an old tower for her sins. The most abominable monsters are in this tower, for example snakes, lizards, newts, turtles, and all kinds of vermin. The people - at least those who have not received an education on this matter, imagine turtles as flying monsters.

[...]

Then, finally, a turtle flew after [the duke of Lichtenstein] in order to tear him apart. However, it had no power over the fleeing man, as he had already passed the boundary [of the Sibyl's realm].

— Schlesische Sagen 1 - Spuk- und Gespenstersagen by Richard Kühnau (Schlesische Sagen, #1) (Page 555 - 556)