Claim: Eberhard I was the first known count of the Sponheim (which went through roughly two main phases during the course of the centuries), while Stephen I was the cousin or brother of Siegfried, who was also a Count of Sponheim, as well as, Count in the Puster Valley and Margrave of the Hungarian March.
Evidence: Eberhard I First known count of the family. There are two main branches which are certainly related, but whose exact relationship is still debated. Stephen I Cousin or brother of Siegfried. Siegfried I Also Count in the Puster Valley and Margrave of the Hungarian March