Complex sentence: The pair probably took refuge with Chlothar, hoping that the Frankish king would intervene and restore them to their sees, and by 617 Justus had been reinstalled to his bishopric.
Split into simpler sentences: The pair probably took refuge with Chlothar, hoping that the Frankish king would intervene and restore them to their sees. By 617 though, Justus had been reinstalled to his bishopric.