Piazza della Repubblica is one of the main squares in Florence and marks the center of the city since Roman times. Sadly, its present rectangular form and architecture reflects the result of the urban "clean-up period" Florence went through during its time as capital of Italy (1865-71: another sad destruction of the period was the tearing down of the 13th century walls that surrounded the city to make way for a wide boulevard).
The Column of Abundance marks the point where the cardus and decumanus maximi met and where the Roman forum stood. During medieval times the area around the column was densely populated. It was the location of the market and the Jewish Ghetto, obligated to live here by Cosimo I. There were many tabernacles and churches. Through the centuries the square retained its medieval look, up until the 18th century when the town council decided to widen the square and clean up the center. Medieval towers, churches, workshops, homes and original seats of the some of the Guilds were destroyed. One can see how the square looked at that time through prints and paintings housed at the museum Firenze com'era (Florence as it was).
The square today does not look exactly as it did even just 150 years ago. For example, the square originally displayed a large bronze equestrian monument to King Vittorio Emanuele II, now located in the square named after him at the entrance to the Cascine Park. The Arch of Triumph also housed several allegorical statues created in clay which were not replaced once they quickly wore down.