The oldest Ent in J.R.R. Tolkien’s The Lord of the Rings is Treebeard.
Treebeard, whose Elvish name is Fangorn, is an ancient shepherd of trees who lives in Fangorn Forest. He is one of the oldest beings in Middle-earth and remembers a world in which the Entwives were still present. His immense age gives him a perspective that reaches back to events long before the War of the Ring.
Merry and Pippin meet Treebeard after escaping from the Orcs who captured them. Their account of Saruman’s destruction of forests helps awaken the Ents to the danger posed by Isengard. The Ents then hold an Entmoot and eventually march against Saruman’s fortress.
Quickbeam, also called Bregalad, is another Ent, but he is younger and more impulsive. “Fangorn” can refer both to Treebeard’s personal name and to the forest, so readers sometimes mistake the place-name for the character’s English name.