Castalia is the goddess of fountains, she associates well with the Naiads. She owns her own fountain on Mount Parnassus, the sacred meeting place of the nine muses; Calliope, Clio, Urania, Euterpe, Erato, Polyhymnia, Terpsichore, Melpomene and their mother and one of the main Titans, Mnemosyne.
Castalia is a kind-hearted goddess, and she lets the nine muses share their sacred hangout on her Mount.
Mount Parnassus is the shared Mountain that has various fountains, and Castalia owns one.
Castalia's official Greek name is Κασταλια.