Anselm, Saint, Archbishop of Canterbury. [Letter to Eulalia, abbess of Shaftesbury, 1106] in Sancti Anselmi Cantuariensis Archiepiscopi Opera Omnia 5.347-48

[Letter from Anselm, archbishop of Canterbury, to Eulalia, abbess of Shaftesbury]
Shortly after his return, archbishop Anselm thanks the abbess and her nuns for their prayers while he was in exile and asks them to pray that the return be prosperous. He also exhorts the nuns to obedience to the abbess and the rule.
Online at Epistolae (See also Bibliographia record).