In his correspondence with Emperor Yang of Sui, the Prince's letter contains the earliest known written instance in which the Japanese archipelago is referred to by a term meaning "land of the rising sun." The Sui Emperor had dispatched a message in 605 that said, "the sovereign of Sui respectfully inquires about the sovereign of Wa," and Shōtoku responded by sponsoring a mission led by Ono no Imoko in 607, who brought along a note reading: "From the sovereign of the land of the rising sun ("hi izuru tokoro") to the sovereign of the land of the setting sun."