Complex sentence: Finlay, pg.500 However, prior to commencing his appointment, Constantine was summoned to Constantinople, where the fragile working relationship between Michael V's successors, the empresses Zoe and Theodora, was breaking down.
Split into simpler sentences: Finlay, pg.500 However, prior to commencing his appointment, Constantine was summoned to Constantinople. There, the fragile working relationship between Michael V's successors, the empresses Zoe and Theodora, was breaking down.