Ephraim Black's pack

"... Did you know Quileutes are supposedly descended from wolves?... That's the legend of our tribe."

- Jacob, telling Bella the Quileutes' history

Ephraim Black's pack was the original shape-shifter pack that formed a treaty with the Cullens. This pack consisted of Ephraim Black, Levi Uley, Quil Ateara II, Joseph Mitchell, and Samuel Grayson.

History
At some point during the early 20th century, the Cullen family moved to the town of Forks near the Quileute reservation. This caused the wolf gene complex to be triggered in four members of the Quileute tribe, who phased into wolves and prepared to attack the Cullens to defend the humans in the area.

However, Carlisle Cullen, the coven leader, was able to pacify the wolves and a treaty was agreed between the two groups, in which the Cullens were not to bite humans or trespass on the Quileutes' land and the Quileutes would not reveal the vampires' existence to the humans.

In the end, this pack left their home, Billy Black and William Mitchell the only two witnessing them to do so. All four of them, old but cheerful, transformed into wolves one last time and disappeared into the woods, never to be seen again.

Twilight
This pack's existence is referenced in Twilight when Jacob Black, Ephraim's descendant, tells Bella the pack's history with the Cullen family.