9th-century Welsh historians

thumb|St. Nennius by Harry Clarke Studios at St. Joseph's Carrickmacross

Asser (; ; died 909) was a Welsh monk from St David's, Dyfed, who became Bishop of Sherborne in the 890s. About 885 he was asked by Alfred the Great to leave St David's and join the circle of learned men whom Alfred was recruiting for his court. After spending a year at Caerwent because of illness, Asser accepted.