In "The Lord of the Rings", what was Gollum's real name?

Gollum is a fictional character from J. R. R. Tolkien's Middle-earth. He was introduced in the 1937 fantasy novel The Hobbit, and became important in its sequel, The Lord of the Rings. Gollum was a Stoor Hobbit of the River-folk, who lived near the Gladden Fields. Originally known as Sméagol, he was corrupted by the One Ring and later named Gollum after his habit of making "a horrible swallowing noise in his throat".

Gollum's real name was Sméagol, and he had once been a member of the secluded branch of the early Stoorish Hobbits. He spent the early years of his life with his extended family under a matriarch, his grandmother. On Sméagol's birthday, he and his relative Déagol went fishing in the Gladden Fields. There, Déagol found the Ring in the riverbed after being pulled into the water by a fish. Sméagol fell immediately under the Ring's influence and demanded it as a birthday present; when Déagol refused, Sméagol strangled him.

Sméagol later used the Ring for thieving, spying and antagonising his friends and relatives, who nicknamed him "Gollum" for the swallowing noise he made in his throat, until his grandmother disowned him. He wandered in the wilderness for a few years until he finally retreated to a deep cavern in the Misty Mountains. The Ring's malignant influence twisted his body and mind, and prolonged his life well beyond its natural limits.