F.45.r of the White Book of Rhydderch showing the beginning of "The dream of Mcasen Wledig". Part one of the two manuscripts of Llyfr Gwyn Rhydderch, comprising the Four Branches of the Mabinogion; Peredur; Macsen Wledig; Lludd a Llefelus; fragments of Owain a Luned; Geraint ac Enid; and an incomplete version of Kulhwch ac Olwen; and a poem by Llywelyn Moel