Cardiff Castle began with the Romans who built a fort here during the 1st century. Three more were constructed until they abandoned the ten-acre site in the late 4th century. The Normans arrived in the late 11th century. They initially constructed a wooden keep protected by a high wall and surrounded by a moat. In the 12th century, the Earl of Gloucester built this shell keep (tower) on top of a motte (man-made hill) in the center of an inner bailey (fortified courtyard). The twelve-sided citadel measures 77 feet wide and 30 feet tall. The Normans remained in control until 1216 AD. You can walk up the fifty steps to see the remnants of this medieval keep.