Emperor Seiwa was the 56th emperor of Japan, reigning from 858 to 876 AD during the Heian period. He was the son of Emperor Montoku and Empress Shōshi. His reign is noted for the consolidation of power by the Fujiwara clan, who played a significant role in the imperial court during this time. Seiwa's era saw the continuation of cultural development, including literature and art. He is also known for his efforts to maintain peace and stability in the realm. After his death, he was succeeded by his son, Emperor Yōzei, marking a transition in the imperial lineage.