KREOUSA (Creusa) was the Okeanid-nymph of the springs of the river Peneios (Peneus) in the Pindos Mountains of Thessalia (northern Greece). She was the wife of the River and the mother of Hypseus, first king of the Lapithai (Lapiths).
CREU′SA (Kreousa). A daughter of Oceanus and Ge. She was a Naid, and became by Peneius the mother of Hypseus, king of the Lapithae, and of Stilbe. (Pind. Pyth. ix. 30; Diod. iv. 69.)
Source: Dictionary of Greek and Roman Biography and Mythology.
CLASSICAL LITERATURE QUOTES
Pindar, Pythian Ode 9 ep1 (trans. Conway) (Greek lyric C5th B.C.) :
"He [Hypseus] was the king of the proud Lapithai (Lapiths), a hero of the seed of the great god Okeanos (Oceanus), child of the second generation, whom in the famous dells of Pindos (Pindus) once the Naias Nymphe, daughter of Gaia (Earth), Kreousa (Creusa) bore, sharing the joys of love with the river-god Peneios (Peneus)."
Diodorus Siculus, Library of History 4. 69. 1 (trans. Oldfather) (Greek historian C1st B.C.) :
"He [the River Peneios (Peneus)] lay with the Nymphe named Kreouse (Creusa) and begat as children Hypseus and Stilbe, and with the latter Apollon lay and begat Lapithes and Kentauros (Centaurus)."
- Pindar, Odes - Greek Lyric C5th B.C.
- Diodorus Siculus, The Library of History - Greek History C1st B.C.
Other references not currently quoted here: Ovid Amores 3.6.31.