Here is the timeline based on what the drama has shown so far (up to episode 16):

460 years ago - HRY and BJS got married in the mortal world to start a love tribulation.

410 years ago - BJS sealed HRY powers in the mortal realm and BJS returned to Nine Heavens realm alone
400 years ago - Both BJS and HRY returned to the Nine Heavens realm, got married, due to a misunderstanding HRY stabbed BJS and imprisoned BJS for 100 years.
300 years ago - BJS broke out of imprisonment, fought HRY, HRY sacrificed her primordial spirit and disappeared.
Current timeline (0)- BJS found HRY as LQY.

Will be updated, once more details is given