Temporally fixing it back onto a very early dynasty (6)
I believe the answer is:
timing
'temporally fixing it back' is the definition.
I can't judge whether this defines the answer.
'onto a very early dynasty' is the wordplay.
'onto' says to put letters next to each other.
'a very early' becomes 'ti' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'dynasty' becomes 'ming' (Chinese dynasty).
'ti'+'ming' is 'TIMING'.
Can you help me to learn more?
(Other definitions for timing that I've seen before include "Supposedly, the secret of great comedy" , "Judgement of when something should be done" , "Choice of moment" , "Entrails used as food" , "Regulating" .)