The Second Doctor was portrayed by Patrick Troughton, whose serials were more action-oriented than those of his predecessor. Additionally, after The Highlanders, stories moved away from the purely historical ones that featured during William Hartnell's tenure; instead, any historical tales also included a science fiction element. Patrick Troughton retained the role until the last episode of The War Games when members of the Doctor's race, the Time Lords, put him on trial for breaking the laws of time and forced him to regenerate.