English folklore developed over many centuries. Some of the characters and stories are present across England, but most belong to specific regions. Common folkloric beings include pixies, giants, elves, bogeymen, trolls, goblins and dwarves. While many legends and folk-customs are thought to be ancient, such as the tales featuring Offa of Angel and Wayland the Smith, others date from after the Norman invasion. The legends featuring Robin Hood and his Merry Men of Sherwood, and their battles with the Sheriff of Nottingham, are among the best-known of these.