Æthelthryth was a 7th-century East Anglian princess who rose to become a queen and eventually an abbess. Born in Exning, she was the daughter of King Anna and lived through various political shifts in the kingdoms of East Anglia, Deira, and Northumbria. After her first marriage to Tondberct, she sought a religious life, later marrying King Ecgfrith of Northumbria before ultimately retiring to the Isle of Ely. There, she established the Ely Abbey, a significant double monastery, where she served as its leader until her death in 679.