Welcome to the Duomo of Pisa, standing in Piazza del Duomo, the square the Italians call Piazza dei Miracoli, the Square of Miracles. Officially this is the Primatial Metropolitan Cathedral of the Assumption of Mary, and it is a medieval Catholic cathedral dedicated to the Assumption of the Virgin Mary. Most visitors arrive with their eyes fixed on the famous leaning bell tower, but the cathedral is the oldest of the three great structures in the square. The Baptistry and the Campanile, the Leaning Tower, came after it. In other words, the cathedral set the tone for everything else you see here. It is a masterpiece of Pisan Romanesque architecture, built when Pisa was a maritime republic at the height of its commercial and political power. Over the next few minutes we will look at how it began, what its striped marble walls are saying, and what survived the terrible fire of 1595. We will end with a ray of sunlight that is worth planning a visit around.