Simplify the following text for a Grade 11 native English-speaking person.
Original: Seimu is regarded by historians as a `` legendary emperor '' and there is a paucity of information about him .
Simplified: Emperor Seimu was the 13th emperor of Japan , according to the traditional order of succession . Historians consider Emperor Seimu to be a legendary person , and the name Seimu-tenn Å was created for him posthumously by later generations .