Board Thread:General Discussion/@comment-24.157.36.219-20130614155339/@comment-9482715-20130614175809

Tiber Septim, founder of the Septim Dynasty of Tamriel, was the next individual to be recognized as Dragonborn. His heirs continued the tradition and were all considered Dragonborn emperors blessed by Akatosh. This lineage ended with the death of Martin Septim during the Oblivion Crisis.

They were blessed by Akatosh and known as DRAGONBORN EMPERORS. They're not actual Dragonborns.