The Tower of the Moon was built in II 3320 on the west shoulder
of Ephel Dśath
by the first two Gondorian Kings,
Isildur and
Anarion,
to keep a watch on
The Land of Shadow.
After being fell in
Sauron's hands
between II 3429 and c. II 3434,
was captured by the
Nazgūl in III
2002 and renamed
Minas Morgul.