Cnapan (alternative spellings Criapan, Knapan or Knappan) is a Welsh form of Celtic medieval football. The game originated in, and seems to have remained largely confined to, the western counties of Wales, especially Carmarthenshire, Ceredigion and Pembrokeshire. According to George Owen of Henllys, in his Description of Pembrokeshire (1603), cnapan had been "extremely popular in Pembrokeshire since greate antiquitie [sic]". Cnapan was one of the traditional ball games played to celebrate Shrovetide and Eastertide in the British Isles. These games were the forerunners of the codified football games first developed by Public Schools which led to the creation of Association football and Rugby football in the 19th century. Cnapan continued to be played until the rising popularity of Rugby Union Football resulted in the game falling into decline.
The earliest documented source for a group ball game in Great Britain comes from Wales. Historia Brittonum (The History of the Britons) written in the ninth-century depicts events during the Dark Ages after the end of Roman rule and forms the basis of the Arthurian legend. The book is accredited to Welsh monk and historian Nennius who supposedly had access to 5th century sources which have not survived. The preface, which appears in several recensions credited to Nennius, is considered by some historians to be a later embellishment by an anonymous writer. Others believe Historia Brittonum to be a collection of stories from the 7th century. Regardless of erroneous historical content, the main text does demonstrate that group ball games were understood in the 9th century and that the author of chapter 41 believed these games were played by the Britons. The oldest surviving transcript dates to c.1100 A.D.