The begining of the full Latin phrase: "tempus fugit, memento mori".
Time flies away, death ought to be remembered.

This motto is written on the banner of the Knights of Columbus, and thereby has accompanied countless beef and beer benefits, bingo games, and wedding receptions.

In the Middle Ages, this sentiment was reinforced by macbre images, memento mori, of corpses, skeletons, death heads, and graphic depictions of decomposition; these were intended to frighten the viewer into remembering the briefness of this life, and the coming dissolution of the body.

A French doctor, in the service of King Louis VI(around 1130), had this inscription, his memento mori, engraved into the cloister of Saint-Victor in Paris:

What we were, you are. What we are, you will become...