Gisela combines the Old German gīsil (pledge, hostage) — a name pledged in alliance. **Gisela of Lotharingia (757-810)** was the daughter of Pepin the Short and **sister of Charlemagne** — abbess of Chelles, learned in Latin, who commissioned major Carolingian manuscripts.
Used widely in German-speaking Europe.
Gisela reduces to three — the number of Carolingian sister.