Son of Thranduil, Lord of the Elves of Mirkwood. He set out from Rivendell with the Company of the Ring, and journeyed with Aragorn and Gimli through the southern lands of Middle-earth during the War of the Ring; he fought at the Battles of the Hornburg and the Pelennor Fields.
Note : At least, Legolas seems to refer to himself as a Silvan Elf: in Eregion, he says '...the Elves of this land were of a race strange to us of the silvan folk...' (The Fellowship of the Ring II 3, The Ring Goes South). This is confusing, because his father Thranduil is elsewhere identified as one of the Sindar. Tolkien touches on this question in his Letters, where he describes Legolas as '...a Woodland Elf, though one of royal and originally Sindarin line.' (The Letters of J.R.R. Tolkien No 297, dated 1967, our italics). The explanation for this is found in the History of Galadriel and Celeborn (in Unfinished Tales), where there's a brief account of the arrival of Thranduil's father Oropher among the Silvan Elves of Greenwood the Great. It's made obvious there that Oropher and his small band of Sindar merged themselves completely with the Silvan people of the Wood, leaving behind their Sindarin inheritance. That's why Oropher's grandson Legolas thinks of himself as a Silvan Elf, rather than one of the Sindar.
Of the Sindarin Elves
Long before the beginning of the First Age, the Elves of the Great Journey travelled westward through the lands of Middle-earth. Coming to the Great River Anduin and the high peaks of the Misty Mountains, some of the Elves of the clan of the Teleri fell away from the journey, and settled in the woodlands east of the Mountains. These were the original Silvan Elves, who lived on either side of the River. At this time in their history, all of this people still lived close together, with some dwelling in the land that would later be called Lórien, and the others settling around the hill of Amon Lanc in the far south of Greenwood the Great.
It must have been in the time these Elves were living closely together that the Silvan Elvish language appeared. As history passed, the Elves would move away from one another, and mingle with other Elvish peoples, so that the Silvan branch of Elvish would eventually become extinct. Nonetheless, relics of that ancient tongue survived in some well-known place-names and personal names, such as Caras Galadhon, Amroth and even Lórien itself.
The Silvan Elves dwelt in their twin woodland realms for many centuries, but in the Second Age the emerging power of Sauron began to drive them apart. Oropher was the ruler of the Elves who dwelt in the Greenwood, and he began to seek safety by moving his people northwards, away from Amon Lanc and away from the Silvan Elves who lived to the west of the Great River.
