In 1567, he changed his name yet again, this time to Tokugawa Ieyasu. As he was a member of the Matsudaira clan, he claimed descent from the Seiwa Genji branch of the Minamoto clan. However, there was no proof the Matsudaira clan are descendants of Emperor Seiwa.[9] Yet, his surname was changed with the permission of the Imperial Court, after writing a petition, and he was bestowed the courtesy title Mikawa-no-kami and the court rank of Junior 5th Rank, Lower Grade