Gollum was born is 2440 and died March 3019 (third age) another name for Gollum is smeagol. Gollum was originally a hobbit who found the One Ring in the river Anduin where Isildur had lost it more than two millennia before coming under it's power. He hid away in the misty mountains and was drawn into the events at the end of the Third Age when he encountered Bilbo Baggins who took the ring from him. 

Gollum first appears in the tale of years in about 2463 when he murders his friend Deagol and steals the ring. The birthrate of 2440 given here is a estimate on the assumption that Gollum would have been about 25 years old at the date. His life span was about 600, this being far longer than a normal hobbit would live, but then this was a side effect of the ring. 

Gollums Identification as a Stoor is based on Gandalfs word in the Lord of the rings - I guess they were hobbit kind akin to the fathers of the fathers of the Stoors. Gollums people split from the other Stoors in the fifteen century on the third age, when troubled times in Eriador led them to migrate back eastwards over the Misty mountains and settle at the banks of the Gladden river.