source: A bastion on the eastern approaches was built later.
target: An extension on the eastern side was built later.
references: An extension on the eastern side was built later. An eastern bastion was built later. A  defense on the eastern side was built later. A fort on the eastern access road was built later. A support on the east was built later. A wall on the east side was built later. A bastion on the eastern side was built later. A fort on the eastern side of the area was built later. Later, it was fortified on the easterrn side. A fortification on the eastern approaches was built later.