Complex sentence: According to Simon Kézai's "Gesta Hunnorum et Hungarorum", the ancestor of the Hermán kindred, knight Herman originated from Nuremberg, who escorted Gisela of Bavaria in 996, who became the wife of Stephen I of Hungary, the future first King of Hungary.
Split into simpler sentences: According to Simon Kézai's "Gesta Hunnorum et Hungarorum", the ancestor of the Hermán kindred, knight Herman originated from Nuremberg, who escorted Gisela of Bavaria to Hungary in 996. She married Stephen I of Hungary, the future first King of Hungary.