The central hall and aisles were covered by wooden roofs with massive oak beams, lacquered and decorated with resplendent shades of silver, white, yellow and black. In the concave and blue border, there were inscriptions in Greek characters, according to
: “the roof is adorned with a distinguished and elegant chiselling, an admirable variety of painting, the colour saffron and ‘ultramarine’ and golds, radiating splendour everywhere; gilded wooden flowers hang from the roof, resembling an inverted pyramid”.
The roof of the central hall, supported by nineteen large trusses, was made “ fairing-like ”, similar to the shape of an upturned ship, with an evangelical reference to “ Peter's ship carrying the faithful ”. Above the beams of the “ chains , a wooden walkway was placed at the centre for the control and maintenance of the entire nave. The system, which is also found in the Cefalù Cathedral , is known as the “ Dromic roof “.