Ely has been an important centre of Christian worship since the seventh century AD. Most of what is known about its history before the Norman Conquest comes from Bede's "Historia ecclesiastica gentis Anglorum" written early in the eighth century and from the "Liber Eliensis", an anonymous chronicle written at Ely some time in the twelfth century, drawing on Bede for the very early years, and covering the history of the community until the twelfth century. According to these sources the first Christian community here was founded by St. Æthelthryth (romanised as "Etheldreda"), daughter of the Anglo-Saxon King Anna of East Anglia, who was born at Exning near Newmarket. She may have acquired land at Ely from her first husband Tondberht, described by Bede as a "prince" of the South Gyrwas. After the end of her second marriage to Ecgfrith, a prince of Northumbria, in 673 she set up and ruled as abbess a dual monastery at Ely for men and for women. When she died, a shrine was built there to her memory. This monastery is recorded as having been destroyed in about 870 in the course of Danish invasions. However, while the lay settlement of the time would have been a minor one, it is likely that a church survived there until its refoundation in the 10th century. The history of the religious community during that period is unclear, but accounts of the refoundation in the tenth century suggest that there had been an establishment of secular priests.