The Big bang was conceived after an empirical discovery made a few decades later than Einstein's theorizing of Special relativity. All our physical space appears to have expanded from singular point, in a manner such that there is no point of origin, that is the Big bang has occurred everywhere at once. So at every point there is an absolute time scale - the precise dating 'ABB' (after the big bang).
Special relativity is in fact a geometry - its space is mathematical, not physical and so there are no preferred reference frames. And indeed there is no real time in it (wikipedia:Eternalism is a good place to start). The physical, 'expanded', space allows for non-separability which explains 'the spooky action at distance' to which Einstein objected - the collapse of wavefunction that occurs everywhere at once.
Mystics have asserted that time is illusory and the idea had gained currency among contemporary scientists and philosophers who believe that Einstein's theory confirms this. Can we assert that this 'block universe' idea (as it is called) has been ultimately proved wrong?