`For myself,' said Faramir, 'I would see the White Tree in flower again in the courts of the kings, and the Silver Crown return, and Minas Tirith in peace...

(LoTR, IV-5)

The Guards of the gate were robed in black, and their helms were of strange shape, high-crowned, with long cheek-guards close-fitting to the face, and above the cheek- guards were set the white wings of sea-birds; but the helms gleamed with a flame of silver, for they were indeed wrought of mithril, heirlooms from the glory of old days.

(LoTR, V-1)

Then Frodo came forward and took the crown from Faramir and bore it to Gandalf; and Aragorn knelt, and Gandalf set the White Crown upon his head, and said: Now come the days of the King, and may they be blessed while the thrones of the Valar endure!

(LoTR, VI-5)

The crown of Gondor was derived from the form of a Númenorean war-helm. In the begining it was indeed a plain helm; and it is said to have been the one that Isildur wore in the Battle of Dagorlad (for the helm of Anárion was crushed by the stone-cast from Barad-dûr that slew him). But in the days of Atanatar Alcarin this was replaced by the jewelled helm that was used in the crowning of Aragorn.

(LoTR, Appendix A)

In the south the realm of Gondor endured, and for a time its splendour grew, until it recalled the wealth and majesty of Númenor ere it fell High towers the people of Gondor built, and strong places, and havens of many ships; and the Winged Crown of the Kings of Men was held in awe by people of many lands and tongues.

(Silm, OF THE RINGS OF POWER AND THE THIRD AGE)