The relationship between times can be qualitative (before, after, etc.) as well as quantitative (3 days before, 397 years after, etc.).
Examples are: ``Mary's salary was raised yesterday,'' ``it happened sometime last week,'' ``it happened within 3 days of Easter,'' ``the Jurassic is sometime after the Triassic,'' ``the French revolution occurred 397 years after the discovering of America.''
Notice that both chronologically indefinite and definite statements can involve relative times.