ago

Eighty-seven years ago. (A "score" is a set of 20 items.) The iconic first line of US President Abraham Lincoln's Gettysburg Address, the speech he delivered at the dedication of the national cemetery in Gettysburg, Pennsylvania. Lincoln gave this speech in 1863—87 years after 1776, the year of the founding of the United States. Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.

a long time ago I only have the faintest memory of that time. It all happened many moons ago.

Also, a while ago. Some time in the past, as in I ran into Barbara a while back but didn't get her new address, or John wrote me a while ago about his new baby. This term uses a while in the sense of "a short or moderate time," a usage dating from about 1300.

A time well before the present, the distant past. For example, I read that book long ago, or The battles of long ago were just as fierce. [Second half of 1300s]