The One Ring to Rule Them all

"'Ash nazg thrakatulûk agh burzum-ishi krimpatul!'                                                        - Sauron""'One ring to rule them all, one ring to find them, One ring to rule them all, and in the darkness blind them!'                                       - Sauron. Translated"

Origin
In the Second Age, Sauron, lieutenant of Melkor, created the One Ring along with others to fight the men and elves. A man named Isildur took it from Sauron, forcing him into hiding.

Creation
Sauron, lieutenant of the black lord Melkor, created the Ring and many others.

Three Rings for the Elven-kings under the sky,           Seven for the Dwarf-lords in their halls of stone,                  Nine for Mortal Men doomed to die,                         One for the Dark Lord on his dark throne.

The one was for Sauron. He turned the nine men into Nazgul. (Ringwraiths) They were under his command.

Loss
A man named Isildur steals the ring from him. Later, Isildur perishes in the Disaster of the Gladden Fields. The ring is lost for a very long time.

Part 1
Sméagol and Déagol are fishing, when Déagol finds the ring. Sméagol steals it, and runs home. He is then called Gollum, because of a sound he made. He runs into a cave, and remains there for over 500 years.

Bilbo's Journey
On Bilbo's Journey, he stumbles into Gollum's cave of gloom. he finds the ring, and barely escapes with his life.

Gandalf's Discovery
Bilbo decides to run away on an adventure. Gandalf convinces him to pass on the ring to Frodo. Gandalf later finds out the evils of the ring.

The Quest Starts
Frodo and his friends are sent to destroy the ring. Both Gollum and the Nazgul are also trying to get it.

The Ring is passed
Gollum tricks Frodo into getting bitten by a spider. Sam thinks he is gone, so he takes the ring.

Returned to Frodo
Frodo is alive, so Sam rescues Frodo, and returns the ring.

The Ending of the Ring and beginning of the 4th age
Gollum steals the ring, and throws it into the fire. The ring is destroyed, and Sauron is defeated.