A Connecticut Yankee in King Arthur's Court by Mark Twain (his real name was Samuel Langhorne Clemens) is one of the first descriptions of a time travelling that was published before Herbert Wells.
An ordinary Yankee from Connecticut during a drunken fight was hit on the head so hard that he came to consciousness and found himself in the court of the King Arthur in the sixth century. A young adventurous man starts to reorganise a medieval legendary kingdom Logress, he “Americanizes” it to the maximum up to the industrial ХІХth century. Even a worshipping solitaire rotates a sewing machine which produces cheap “saint” shirts. But many people are not happy with this situation, so the Yankees declare the war...