Today we are the basilica of Santa Maria in Aracoeli, next to Piazza del Campidoglio and Piazza Venezia above, as usual 
in search of curiosities and legends.
First, it is known that many of the early Christian churches were born on existing buildings dedicated to other cults. Even our church was probably born on the place where the temple of Juno Moneta (ie “Juno warning”). The first point of interest is that this hill was also localized the mint of Ancient Rome, so our Italian word “money” is derived from this temple of Juno!
But other words are related to this place, right here was also interpreted the will of the gods through the flight and song of birds, and the priests who carried out these observations were called “wishes” … from which our word “hope.”
But back in our church: the debate about which is the oldest church in Rome is open … maybe St. John Lateran? Well … according to legend, the original altar of the basilica of Santa Maria in Aracoeli is the only Christian altar in the world to have been founded even before the birth of Christ! How is it possible?
The legend begins narrating how the Sibyl Tiburtina, consulted by the Emperor Augustus, announce that “from the sky will come a king who will reign in human form for centuries and judge the world.” Then the emperor, who was in her room, is witnessing an apparition: a virgin on the altar is holding a baby and a voice announces that this is the altar of the “Lord of Heaven.” Augustus falls to his knees in adoration.
Clearly, the Christian communities in the Middle Ages took interpret “a posteriori” this vision as a proclamation of the coming of the Messiah.
According to legend, Augustus was very impressed by the vision, so did spend, just near his room, an altar to the “Lord of Heaven” near future. For whom the word “Ara Coeli”, or “Altar of Heaven”, derives from this altar at the chamber of the emperor, altar as the first nucleus of the church, built a few centuries later.
An altar Christian and pre-Christian, at the apartment of Augustus … but those who believe? Well …. a little “sign” of this legend, it can still be found today: we enter the Basilica, and examine the third column of the row on the left. On this column, at the top, we read an ancient engraving: “A cubiculo Augustorum.” And yes, they all agree that this column, which now supports the nave existed before the church, and originally was holding the apartment of the Emperor!