Æthelthryth (also Etheldreda, Ediltrudis, Audrey or Awdrey) (c. 630 - June 23 679) was a popular Anglo-Saxon saint. She was probably born at Exning , near Newmarket in Suffolk, a daughter of Anna, King of East Anglia. She made an early first marriage (abt. 652) to Tondberct, chief of the South Gyrvians, but is alleged to have remained a virgin until her husband's death in 655, whereupon she retired to the Isle of Ely.

She then married Ecgfrith, King of Northumbria, but took the veil shortly after Ecgfrith's accession to the throne, a step which possibly led to his long quarrel with Wilfrid archbishop of York. One account holds that while Ecgfrith initially agreed that she should continue to be chaste, in about 672, he wished to consummate their marriage, and even attempted to bribe Wilfrid to use his influence on the queen to convince her. Ecgfrith married a second wife, Eormenburg , before 678, the year in which he expelled Wilfrid from his kingdom.

According to the Anglo-Saxon Chronicle, she founded the monastery at Ely in 673. Bede tells how after her death, her bones were disinterred by her sister and successor, Abbess Seaxburh, and buried in a white, marble coffin from Cambridge.

The common version of Etheldreda's name was St. Awdrey, which is the origin of the word tawdry - because cheap souvenirs were sold at an annual fair held in her name in Ely.