Michelangelo's design for Capitoline Hill, now home to the Capitoline Museums. Engraved by Étienne Dupérac, 1568. The Capitoline Museums (Italian Musei Capitolini) are a group of art and archeological museums in Piazza del Campidoglio, on top of the famous Capitoline Hill in Rome, Italy. The museums are contained in three palazzi surrounding a central trapezoidal piazza in a plan conceived by Michelangelo Buonarroti in 1536 and executed over a period of over 400 years. The history of the museums can be traced to 1471, when Pope Sixtus IV donated a collection of important ancient bronzes to the people of Rome and located them on Capitoline Hill. Since then, the museums' collection has grown to include a large number of ancient Roman statues, inscriptions, and other artifacts; a collection of medieval and Renaissance art; and collections of jewels, coins, and other items. The museums are owned and operated by the municipality of Rome. The statue of a mounted rider in the centre of the piazza is of the Emperor Marcus Aurelius. It is a copy, the original being housed on-site in the Capitoline museum. Many Roman statues were destroyed on the orders of Christian Church authorities in the middle ages; this statue was preserved in the erroneous belief that it depicted the Emperor Constantine, who made Christianity the official state religion of the Roman empire.
The three main buildings of the Capitoline Museums are:
the Palazzo Senatorio, built in the 12th century and modified according to Michelangelo's designs;
the Palazzo dei Conservatori, built in the mid-15th century and redesigned by Michelangelo with the first use of the giant order column design; and the Palazzo Nuovo, built in the 17th century with an identical exterior design to the Palazzo dei Conservatori, which it faces across the palazzo.
In addition, the 16th century Palazzo Caffarelli-Clementino, located off the piazza adjacent to the Palazzo dei Conservatori, was added to the museum complex in the early 20th century.

Capitoline Museum
The Capitoline Museum is located on two floors in the Palazzo Nuovo, and contains statues, inscriptions, sarcophagi, busts, mosaics, and other ancient Roman artifacts.

Palazzo dei Conservatori Museum
The Palazzo dei Conservatori houses a museum of the same name, containing ancient sculpture, mostly Roman but also Greek and Egyptian. As of 2005, the Palazzo dei Conservatori Museum is currently undergoing major renovations, and most of the exhibition spaces are closed to public access. The second floor of the building is occupied by the Conservator's Apartment, a space now open to the public and housing such famous works as the bronze she-wolf nursing Romulus and Remus, which has become the emblem of Rome. The Conservator's Apartment is distinguished by elaborate interior decorations, including frescoes, stuccos, tapestries, and carved ceilings and doors. The third floor of the Palazzo dei Conservatori houses the Capitoline Art Gallery, housing the museums' painting and applied art galleries. The Capitoline Coin Cabinet, containing collections of coins, medals, jewels, and jewelry, is located in the attached Palazzo Caffarelli-Clementino.
In the Hall of the Galatian (Palazzo Nuovo) it can also be appreciated the marble statue of the "Dying Gaul" also called “Capitoline Gaul”.

Other scultures at the museum include:
the statue of Capitoline Venus, from an original by Praxiteles (4th century BC), the colossal statue restored as Oceanus, located at the museum courtyard (Palazzo Nuovo), fragments of the Colossal statue of Constantine originally in the Basilica of Maxentius, a fragment of the Tabula Iliaca located at the Hall of the Doves (Palazzo Nuovo), the famous Bernini's Medusa, the statue of Cupid and Psyche, placed at the Hall of the Galatian (Palazzo Nuovo), the impressive relief from the honorary monument to Marcus Aurelius, located at the main staircase at the Palazzo dei Conservatori.

Architecture and design
The existing design of the Piazza del Campidoglio and the surrounding palazzos was created by famed Renaissance artist and architect Michelangelo Buonarroti. The commission for the design was from the Farnese Pope Paul III, who wanted a symbol of the new Rome to impress Charles V, Holy Roman Emperor, who was expected in 1538. The location, the Capitoline Hill, had once been the heart of pagan Rome, though that connection was largely obscured by its other role as the center of the civic government of Rome. As a result, the piazza was already surrounded by existing buildings. Approximately in the middle, not to Michelangelo's liking, stood the only equestrian bronze to have survived since Antiquity, Marcus Aurelius, the philosopher emperor. Michelangelo provided an unassuming pedestal for it. The only reason that this sculpture survived the thorn of christians in the Middle Ages, is because it was thought that this wasn't Marcus Aurelius, but Emperor Constantine, who was thought to be the first christian emperor. Michelangelo completed a design for the piazza and remodelling of the surrounding palazzos. However, executing the design was slow work: little was actually completed in Michelangelo's lifetime, but work continued faithfully to his designs and the Campidoglio was completed in the 17th century, except for the paving design. Michelangelo provided new fronts to the two official buildings of Rome's civic government, which very approximately faced each other, the Palazzo dei Conservatori and the Palazzo Senatore, which had been built over the Tabularium that had once housed the archives of ancient Rome. Michelangelo devised a monumental stair (the Cordonata) to reach the high piazza, so that the Campidoglio resolutely turned its back on the Roman Forum that it had once commanded, and he gave the space a new building at the far end, to close the vista. The Cordonata is a ramped stair that can be accessed on horseback by the sufficiently great, though it was not in place when Emperor Charles arrived, and the imperial party had to scramble up the slope from the Forum to view the works in progress. The unfolding sequence, Cordonata piazza and the central palazzo are the first urban introduction of the "cult of the axis" that would come to occupy Italian garden plans and reach fruition in France. The Palazzo dei Conservatori was the first use of a giant order that spanned two stories, here with a range of Corinthian pilasters and subsidiary Ionic columns flanking the ground-floor loggia openings and the second floor windows. Another giant order would serve later for the exterior of St. Peter's Basilica. A balustrade punctuated by sculptures atop the giant pilasters capped the composition, one of the most influential of Michelangelo's designs. The sole arched motif in the entire design are the segmental pediments over the windows, which give a slight spring to the completely angular vertical-horizontal balance of the design. The bird's-eye view of the engraving by Étienne Dupérac shows Michelangelo's solution to the problems of the space in the Piazza del Campidoglio. Even with their new facades centering them on the new palazzo at the rear, the space was a trapezoid, and the facades did not face each other squarely. Worse than that, the whole site sloped (to the left in the engraving). Michelangelo's solution was radical. Since no "perfect" forms would work, his apparent oval in the paving is actually egg-shaped, narrower at one end. The travertine design set into the paving is perfectly level: around its perimeter, low steps arise and die away into the paving as the slope requires. Its center springs slightly, so that one senses that one is standing on the exposed segment of a gigantic egg all but buried at the center of the city at the center of the world, as Michelangelo's historian Charles de Tolnay pointed out. An interlaced twelve-pointed star makes a subtle reference to the constellations, revolving around this space called Caput mundi, the "head of the world". The paving design was never executed by the popes, who may have detected a subtext of non-Christian meaning. Benito Mussolini ordered the paving completed to Michelangelo's design — in 1940.