jadis - of long ago, formerly.

Cette ville a conservé sa splendeur de jadis.

This town has kept its former splendor.

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[This word's etymology is interesting. It comes from an old French expression "ja a dis," meaning roughly "it has been days."  Ja is a form of the modern word déjà, a stands for "il y a," and dis means "days," as in lundi, mardi, etc.]