A title given to Círdan the Shipwright
Círdan the Shipwright was one of the oldest and most venerable of the Elves of Middle-earth. During the First Age he was lord of the Falas, a shoreland region in which stood two great havens, Brithombar and Eglarest. After the defeat of the Elves in the great battle of the Nirnaeth Arnoediad, the forces of Morgoth broke down the walls of Círdan's Havens and laid them in ruin. Círdan himself escaped the destruction aboard a ship, in which he sailed to the Isle of Balar and created a new haven and refuge far from Morgoth's ravaging armies.
Thus Círdan had been a lord of Havens back into the history of Middle-earth, but the title 'Lord of the Havens' is only used after the beginning of the Second Age, when he served High King Gil-galad as the Master of the Grey Havens. These Grey Havens, or Mithlond in Elvish, were founded on the new western coasts of Middle-earth in Lindon, after the Sea had claimed most of the lands westward of the Blue Mountains. From there Círdan oversaw the making of the ships that would sail out into the Great Sea and on to Aman in the Uttermost West.
The importance of Círdan as Lord of the Havens is shown by the fact that he bore, for a time, one of the Three Rings of the Elves. When Celebrimbor sent two of the Rings north to Gil-galad for safekeeping, Gil-galad passed one of them, Narya the Ring of Fire, to Círdan. Círdan passed it on in turn, for he was at the Grey Havens when the Wizards sailed into harbour. He chose to grant the Ring to one among them - the one later named Mithrandir or Gandalf - as an aid in his work in Middle-earth.
The Grey Havens had been founded at the very beginning of the Second Age, and still stood at the end of the Third. Círdan had been their Lord for all this time; as he watched the White Ship carry the Ring-bearers out from his harbour, he had held the Lordship of the Havens for a period of nearly six and a half millennia. At some point in the Fourth Age, it seems, Círdan finally boarded the Last Ship to sail from Mithlond, and passed from Middle-earth after thousands of years as Lord of the Havens.