Asser (d. 908/9) was a Welsh monk who became Bishop of Sherborne in the 890s. It is not certain whether his birth name was "Gwyn" (or "Guinn"), which is Welsh for "blessed" (or "blessedness"), or "Asser" (or "Asher"), which is Hebrew for "blessed" and the name of Jacob's eighth son in the Bible. Hebrew names were often given to babies in Wales at the time, but it was also common to adopt a Biblical name when becoming a monk or priest, so the question remains open. Asser was a monk at St. David's in what was then the kingdom of Dyfed, but nothing is known of his earlier life, and not much is known about any of it.

He went to work for King Alfred the Great in Wessex, and part of his work was to help the king with the books he translated. In 893 Asser wrote his own Life of King Alfred that is the best source of information modern historians have about any early king in Britain. At some time between 892 and 900 Asser became Bishop of Sherborne -- he had already been a bishop, but whether he was Bishop of St. David's or a suffragan bishop of Sherborne while Wulfsige was its bishop is not clear, although Giraldus Cambrensis listed Asser as a bishop of St. David's in Itinerarium Cambriae, which he wrote in 1191.

During the 19th and 20th centuries, several scholars asserted that Asser's biography of King Alfred was not authentic but a forgery; at least one scholar claimed the forger was Bishop Leofric of Devon and Cornwall (became bishop 1046, died 1072). The bases for those assertions did not stand up to examination, and the Life is still acknowledged as authentic by all reputable authorities. It is readily available in various editions of books and on the Internet.

HTML full text of Asser's Life of King Alfred