I suppose that Umayyads, Ummayads or Ommayads are the first dynasty (reigned until 749) of the Islamic empire after the four caliphate era. They are followed by Abbasids (which are different than Abbadids) holding the caliphate between 749-1258. As far as I know Abbadids are not a continuum of Abbasids dynasty and an entirely separate Arab dynasty ErdemTuzun.