Michelangelo's piazza had a profound political purpose. In ancient times, the temple of Jupiter stood on this hill. It looked along the ridge that became the Palatine Hill, and down over the valley that became the Forum. Its final incarnation, built by Tarquinus Superbus in the sixth century BC, was enormous.
Under the Republic and then the Empire it remained a temple, sacred to Jove. It stood a the head of the Via Sacra, the most important road of classical Rome, overseeing the white-robed Vestal Virgins, the slaves in victory processions, the sacrifices and prayers of millions. For thousands of years, the axis of the hill was south east.
The anxious Popes of the renaissance both relied on that history and turned away from it. For them, St Peter's was the centre of power, no longer the Forum. Paul III had the Piazza reoriented to face west north west. Toward the basilica.
The southern edge of the square, shown here, is Rome's Town Hall, its stairs also deigned by Michelangelo. The Palazzo dei Conservatori (to the right) was already in place, but Michelangelo created a new façade, and had the Palazzo Nuovo built opposite to match. These are both angled slightly to focus on the Town Hall.
Michelangelo was old when he designed this, and the square wasn't actually finished until the seventeenth century. One thing he did was to bring to this square the magnificent equestrian statue of Marcus Aurelius, which had stood oustside San Giovanni Lateran for years. More of that in a moment.
The two Palazzi are now home to the magnificent Capitolini musueums. Before we visited them, we strolled around the hill, looking at the views, and visited S Maria in Aracoeli, the church behind the unprepossessing red brick facade at the top of the ancient steps.