Complex sentence: Most scholars agree that the cathedral was rebuilt in the 1550s or 1560s; it was formerly ringed by four smaller chapels, in an arrangement reminiscent of the Annunciation Cathedral in the Kremlin.
Split into simpler sentences: Most scholars agree that the cathedral was rebuilt in the 1550s or 1560s. It was formerly ringed by four smaller chapels, in an arrangement reminiscent of the Annunciation Cathedral in the Kremlin.