 In 1986, the Knight's Castle was replaced by similar-sized 6074 Black Falcon's Fortress which had the same type of minifigures (including the two mounted knights).The main difference was in the structure as the two defense towers had been moved to the front, and were made with more rounded (octagonal) corner pieces, leaving room in the back for a small roofed residence/chapel with a yellow Tudor wall.6074 was quite unique because it was the first set to include the octagonal corner pieces and the yellow Tudor wall, as well as the only set to have a blue Black Falcons flag.