Eorcenberht died on 14 July 664, in an outbreak of plague that occurred that year. After her husband's death, Seaxburh remained in Kent to bring up her children. She played an important political and religious influence in the kingdom: she acted as regent for her son Ecgberht, ruling Kent until her young son came of age, and was the founder of Kent's first abbey for women at Milton. Thereafter, Seaxburh became a nun and founded the abbey of Minster-in-Sheppey. According to the "Liber Eliensis", a 12th-century chronicle and history written at Ely, an English source related that Seaxburh received "the veil of holiness" from Theodore, the Archbishop of Canterbury, in her church on the Isle of Sheppey and that her daughter Eormenhild also became a nun there. Seaxburh is said by her hagiographer to have sought refuge as a nun after living a secular role that she had found hard to tolerate: having reluctantly submitted to marriage, she hastened from queenhood to "a timely widowhood and a hasty withdrawal to the religious life", according to Susan Ridyard.