The Daijō-sai, or the Great Thanksgiving Festival, is the third and most important—and also the most controversial of the inauguration rituals, because it is the one in which the Emperor is united to his Imperial Ancestress, sun-goddess Amaterasu-ōmikami, in such a way as to share in a unique way in her divinity. The ceremony is not mentioned in the Constitution imposed by the American occupation forces, and so its present constitutionality was questioned at the time of the accession of the present Emperor Akihito.