Thranduil, son of Oropher, was an Elven king who ruled over the Woodland Realm in the Second and Third Ages. Though inherently cautious, he eventually committed his kingdom to fighting against Sauron in the War of the Ring. He was the father of the Elven prince of Mirkwood, Legolas, who was a member of the Fellowship of the Ring.
In The Hobbit, Thranduil is only referred to as the Elvenking.
Biography
First and Second Ages
Thranduil was the only son of Oropher, the King of the Woodland Realm. He was born sometime during the late First Age in Doriath before its fall. At the beginning of the Second Age, the Sindar travelled east and Oropher eventually founded Greenwood the Great.
In SA 3434, Thranduil and his father fought in the Battle of Dagorlad. Oropher was slain and Thranduil returned to Greenwood with roughly a third of the army that had marched to war. He claimed his inheritance and some time before TA 1000 inherited Oropher's title of King of the Woodland Realm, reigning over the south of Greenwood the Great.
Third Age
At the beginning of Thranduil's reign his kingdom encompassed all of Greenwood the Great and was known as the Woodland Realm, but as the Third Age progressed, the shadow of the Necromancer advanced, and the Greenwood grew dark and became known as Mirkwood, and became infested with Orcs and giant spiders. The Wood-elves of Mirkwood were reduced in number and retreated to lands in the north of Mirkwood. By the time of the events of The Lord of the Rings Thranduil's title was King of the Elves of Northern Mirkwood.
In his realm, both Sindarin and Silvan Elvish were spoken, though not all members of his Woodland folk spoke Sindarin.
The Quest of Erebor
When Thorin Oakenshield and his party of Dwarves entered northern Mirkwood, Thranduil captured Thorin and locked him up in a secure room when he refused to divulge his true intentions. The Dwarves were treated well, with plenty of food and drink. Subsequently, when the rest of the Dwarves had been captured by the elves, Thranduil had them unbound and treated them as his guests (save that they were not allowed to leave the caverns), until they angered him by being surly and impolite, insulting him for keeping them as prisoners, and not revealing why they had entered the forest, after which he gave them each their own cell. He did not tell them that Thorin was also his prisoner.
Thranduil: "What were you doing in the forest?"
Thorin: "Looking for food and drink, because we were starving."
Thranduil: "Take him away and keep him safe, until he feels inclined to tell the truth, even if he waits a hundred years." —The Hobbit, "Flies and Spiders"
After the death of the Dragon Smaug, Thranduil supported Bard the Bowman's claim of a share of the treasure the dwarves recovered from the Lonely Mountain, since Bard was a descendant of Lord Girion of Dale, and the treasure of that town had been taken by Smaug to the Lonely Mountain.
Thranduil led the elven forces in the Battle of the Five Armies. His army was position on the southern side of the Mountain, and was the first to charge.
After the battle and of Thorin's death, Thranduil took Orcrist, which was previously confiscated in Mirkwood, and laid it upon Thorin's tomb. The treasure was divided among Elves and Men, and Thranduil received the emeralds of Girion. Bilbo, Gandalf and Beorn traveled with the elf-host back to Mirkwood but would not stay in the woods, even when Thranduil asked them to.
When Bilbo and Gandalf bade farewell, Bilbo gave Thranduil a necklace of silver and pearls. The king gave Bilbo the title of "elf-friend" and returned with his host in their halls.
War of the Ring
During the War of the Ring, he sent his son Legolas to Rivendell, along with other Elves, to report Gollum's escape from Mirkwood. The gradually-established friendship between the dwarf Gimli and Legolas later helped to reconcile Thranduil's people with the Dwarves.
When the forces from Dol Guldur later attacked Mirkwood, Thranduil repulsed an attack and had the victory. His actions were in concert with the Dwarves and the Men of Dale against the Easterlings who attacked from the East. He came into an agreement with Celeborn that the southern part of Mirkwood would be counted as East Lórien. Thranduil took the northern region as far as the mountains; the wide forest between Mirkwood and East Lórien was given to the Beornings. By this time also, Thranduil renamed Mirkwood Eryn Lasgalen, the Wood of Greenleaves.
Fourth Age
After the fall of Sauron, Thranduil fixed the southern boundary of his realm as the Mountains of Mirkwood, and his realm flourished well into the Fourth Age. He may have stayed on as the king of the Great Forest or left Middle-earth and departed to the Undying Lands.
Etymology
Thranduil is a Sindarin word for "Vigorous spring", from tharan ("vigorous") and ethuil ("spring"). It was said that the name "Thranduil" was of Lemberin language (later Avarin or Telerian), along with other Sindarin names such as Legolas, Nimrodel, and Amroth among others.
Titles
Thranduil first appears as a character in The Hobbit, where he is not named. Tolkien refers to him as the elf-king or the king, and also by the titles Elvenking and King of the Elves of the Wood. The name Thranduil first appears in The Lord of the Rings, in which his title was given as the King of the Elves of Northern Mirkwood. Elsewhere in Tolkien's writings he was also referred to as King of the Woodland Realm, a title he inherited from his father.
