Henry William Carless Davis, 1911 Encyclopædia Britannica, Volume 19… (1911)
“ NENNIUS (fl. 796) , a Welsh writer to whom we owe the Historia Britonum, lived and wrote in Brecknock or Radnor. His work is known to us through thirty manuscripts; but the earliest of these cannot be dated much earlier than the year 1000; and all are defaced by interpolations which give to the work so confused a character that critics were long disposed to treat it as an unskilful forgery. ”
