When Constantine established the city on the hill as the capital of the Roman Empire, one of his first projects was the construction of a forum, built just outside the then-city walls. The forum was circular with two monumental gates, and at its center Constantine erected a monumental column carved of red porphyry stone and topped by a Corinthian capital bearing his own likeness. A drawing by Melchior Lorick (1561) contains an illustration of the column showing a relief on the north, Senate-facing side of the base.
The Forum of Constantine is said to have been the inspiration for Bernini in his conception of St. Peter's Square in Rome. The column has been a victim of earthquakes and elements: In A.D. 418, part of the base cracked, prompting its reinforcement via the use of a ringed metal brace (additional braces were added later), and in 1106, the statue of Constantine was toppled by a hurricane. Manuel Komnenos presided over the first restoration of the monument, placing a simple cross atop the column in place of the destroyed statue of the emperor. Since then, periodic repairs have been done to cracks in the marble, and in 2003 a full-fledged, comprehensive restoration was begun.