Complex sentence: Under the Hasmonean's, the Baris was rebuilt or repurposed as a fortress-residence used by the High Priest, which is referred to by Josephus as the "Baris" citadel.
Split into simpler sentences: Under the Hasmonean's, the Baris was rebuilt or repurposed as a fortress-residence. This is prominently referred to by Josephus as the "Baris" citadel.