What is "ab aeterno"

adv. From time immemorial; from an infinitely remote point in the past.Philip Babcock Gove (editor), ''Webster's Third International Dictionary of the English Language Unabridged'', G. & C. Merriam Co. (1976), ISBN 0-87779-101-5.

"Ab Aeterno" is the ninth television episode of the American Broadcasting Company's sixth season of the serial drama television series Lost and 112th episode overall. The episode aired on March 23, 2010.

In an extended flashback, after the death of his wife, Richard Alpert ( Nestor Carbonell) arrives on the island as a slave on the Black Rock in the 19th century. He then encounters the Man in Black ( Titus Welliver) and Jacob ( Mark Pellegrino), both of whom offer him different deals in exchange for his allegiance.

The title is Latin for "from eternity", a phrase used to mean "since the beginning" or "for long ages" (very loosely translated as "your life now will be either heaven or hell throughout eternity"); this references the agelessness granted to Richard by Jacob as a reward for his service. "Ab Aeterno" was watched by 9 million American viewers and received critical acclaim by critics and audiences alike.