the black book of carmarthen is the earliest surviving medieval manuscript written solely in welsh , and contains some of the earliest references to arthur and merlin .
the book is a collection of 9th-12th century poetry along both religious and secular lines , and draws on the traditions of the welsh folk-heroes and legends of the dark ages .
` it 's easy to think we know all we can know about a manuscript like the black book but to see these ghosts from the past brought back to life in front of our eyes has been incredibly exciting .