After Emperor Kotoku died at Naniwa no Miya in November 654, the retired Empress Kogyoku ascended the throne again (Choso [a second accession to the imperial throne]) at Itabuki no Miya Palace early in the following year, becoming Empress Saimei.
654年（白雉5）10月孝徳天皇が難波宮で没すると翌年の初めに皇極上皇は板蓋宮において再度即位（重祚）し、斉明天皇となった。