Laws relating to the imperial house must be approved by the Diet. Under the old system, the Imperial Household Law was separate from and equal with the constitution. After the war, the imperial family's extensive estates were confiscated and its finances placed under control of the Imperial Household Agency, part of the Office of the Prime Minister and theoretically subject to the Diet. In practice it remains a bastion of conservatism, its officials shrouding the activities of the emperor and his family behind a "chrysanthemum curtain" (the chrysanthemum being the crest of the imperial house) to maintain an aura of sanctity. Despite knowledge of his illness among the press corps and other observers, details about the late Emperor Hirohito's state of health in 1988 and 1989 were tightly controlled.