Following the instructions of his father, Prince Ogura, he received the name KIYOHARA no Mahito in 804 and demoted from nobility to subject, becoming the founder of the Kiyohara clan, which continued for generations.
延暦23年（804年）、父の小倉王の上表により清原真人姓を賜り臣籍降下、後世に続く清原氏の始祖となる。