Orthanc.

Mount Fang ( Human translation of the Sindarin word Orthanc.)

Cunning Mind. ( Rohirrim meaning of the word Orthanc.)

In Isengard stands the tower Orthanc, it was build by the men of Númenor in black stone. It was tall, 400 feet it raised above the plain below, and had many secrets. From the ground a stair raised to the only door into the tower. At the top was a chamber, Sarumans chamber. Above the top-chamber, between the four horns was a roofless narrow room, the floor was polished stone written with strange signs. From buttom to top a stair ran inside the tower with many thousend steps and many windows was cut into the climbing walls. When the realms in exile Arnor and Gondor was founded Orthanc became property of the King in Gondor and a Palantiri was placed there by Anarion.

The tower was black and gleaming looking like it was riven out from the bones of the earth and not made by men, four piers of many-sided stone were welded into one, but near the summit they opened into four horns with pinnacles sharp as points of spear and keen-edged as knifes. The black rock itself was hard and unbreakable. On the Eastern side was, hewn by the same type of rock, mounted a flight of twenty-seven broad stairs up to the treshold of the great door and above the door was a balcony hedged with iron bars.

Saruman soon after the crowning of Frealaf as Lord of the Mark in T.A.2759, Beren the Steward of Gondor gave Saruman leave to settle himself in Isengard and gave him the 3 black keys to Orthanc.

Before Saruman the valley of Isengard with Orthanc had beeen green and fair, it was a strong and beuatyful place and great lords, wardens of Gondor had dwelt there and wise people had used the tower for watching the stars. After the destruction of the One Ring Aragorn Gimli and Gandalf search the tower and in a secret locker in Sarumans chamber they found a box with the chain in which Isildur long ago had kept the One Ring, and they also found the Elendilmir he wore. Those two heirlooms provides us with the evidence that Saruman did find the place where Isildur died but he came too late for the Ring already found by Gollum.