Gollum’s original name in J.R.R. Tolkien’s Middle-earth stories was Sméagol.
Sméagol was a member of a river-dwelling people related to the Hobbits. On his birthday, he saw the Ring while fishing with his relative Déagol. Sméagol murdered Déagol to obtain it, beginning the long corruption that eventually turned him into the creature known as Gollum.
The name Gollum comes from the choking, swallowing sounds he repeatedly makes. Tolkien presents Sméagol and Gollum as two aspects of one deeply divided character: traces of Sméagol remain, but centuries of isolation and the Ring’s influence have transformed him.
Déagol is often mixed up with Sméagol because both appear in the Ring’s discovery scene. Déagol finds the Ring first, while Sméagol takes it by force. In The Lord of the Rings, Gollum’s history helps explain both his obsession with the Ring and his complicated relationship with Frodo and Sam.