In many ways, Piazza del Duomo is the key to the city, and essential to understanding everything that comes after. Tour groups circle around the great spiritual monuments of medieval Florence like sharks around their prey, preyed on in turn by postcard vendors and portrait painters. An occasional street musician serenades the human carnival from a hundred nations, while ambulances of a medieval first-aid brotherhood stand at the ready in case anyone swoons from ecstasy or art-glut. As bewildering as it often is, however, the Piazza del Duomo is the best introduction to this often bewildering city.
It's a peculiarity of Tuscan cities to have Cathedral complexes set away from the centre, as at Pisa or Lucca. In Florence's case, the city grew enough to surround and embrace the Cathedral of Santa Reparata and the old Baptistry—a building more important to the Florentines than any cathedral, one which occupies the site of an ancient temple to the city's ruling deity Mars.
Images by PD Art, R. Thiele, Creative Commons License