Pyrene (Πυρήνη) is from the Greek pyr (fire). The princess of Bebryces, beloved by Heracles, who died alone in the great mountain range — **the Pyrenees mountains are named after her**. Heracles raised stone cairns over her body that became the peaks.
Featured in Silius Italicus's Punica.
Pyrene reduces to one — the number of Greek mountain namesake.