Sei Shonagon was a Japanese author and a court lady who served the Empress Teishi during the middle Heian Period. She is known as the author of makura no soshi. She was the daughter of Kiyohara no Motosuke who was a Heian period waka poet . She married Tachibana Norimitsu at the age of 16. There are no details about Shonagon's life after the death of the Empress Teishi.