The main statue in the Campo de'Fiori is dedicated to the philosopher Giordano Bruno who lived from 1548 to 1600. He initially went to school and became a priest and focused his studies mnemonic techniques. To avoid the Inquisition, he often fled cities and finally abandoned his order and became a Calvinist. As a scientist, he was often made fun of for believing that the earth does go around the sun. He tried to teach at universities throughout Europe, but only acquired positions at a few. He was eventually charged with blasphemy and heresy and sentenced to death. The statue was erected in 1889 and faces the Vatican. For more information or to see where this picture came from visit http://en.wikipedia.org/wiki/Giordano_Bruno.
After reading further information, I have learned that Bruno's death made him a hero for anti-clerical liberals. Bruno traveled around Europe for fifteen years and was even a spy for the English government. He was eventually betrayed to the Romans by his hosts in Venice. He was sent back to Rome and was burned at the stake seven days later, right where his statue now stands. This information can be found in the Blue Guide Rome published by Somerset Norton.