The Pantheon (meaning 'temple of every god') is a former Roman temple, now a church, on the site of an earlier temple commissioned by Marcus Agrippa during the reign of Augustus (27 BC-14 AD). The present building was completed by the emperor Hadrian and probably dedicated about 126 AD. He retained Agrippa's original inscription, which has confused its date of construction as the original Pantheon burnt down so it is not certain when the present one was built.
The building is circular with a portico of large granite Corinthian columns under a pediment. A rectangular vestibule links the porch to the rotunda, which is under a coffered concrete dome, with a central opening (oculus) to the sky. Almost two thousand years after it was built, the Pantheon's dome is still the world's largest unreinforced concrete dome. The height to the oculus and the diameter of the interior circle are the same, 43.3 metres.
Pantheon is one of the best-preserved of all Ancient Roman buildings. The Pantheon's large circular domed cella, with a conventional temple portico front, is 'unique' in Roman architecture. Nevertheless, it became a standard exemplar when classical styles were revived, and has been copied many times by modern architects.
Pantheon was converted into the church of St. Mary of the Martyrs in 608 CE. In 1270 a bell tower was added to the porch roof and later removed. Also, at some time in the Middle Ages the left side of the porch was damaged which necessitated the replacement of three columns. The first came from Domitian's villa at Castelgandolfo and was added in 1626. The other two columns came from the Baths of Nero and were added in 1666. However, these additions were rose-pink in colour whilst originally the front eight columns of the porch were all grey and only the internal four were pink Aswan. Also in 1626 Pope Urban VIII removed all of the bronze girders from the porch roof and recast the metal into 80 canons for the city's Castel Sant'Angelo. The presence of these girders suggests that the porch roof originally had heavy marble tiles.
Despite these changes the Pantheon is one of the best preserved ancient monuments in the world and it still has an important function and status today as within it are the tombs of the Italian monarchy from 1870-1946 and another notable tomb is that of Raphael (1483-1520 CE).
Pantheon is visited by over 6 million people annually. It is part of the UNESCO World Heritage Site Historic Centre of Rome.
References:The Palazzo Colonna is a palatial block of buildings built in part over ruins of an old Roman Serapeum, and has belonged to the prestigious Colonna family for over twenty generations.
The first part of the palace dates from the 13th century, and tradition holds that the building hosted Dante in his visit to Rome. The first documentary mention notes that the property hosted Cardinal Giovanni and Giacomo Colonna in the 13th century. It was also home to Cardinal Oddone Colonna before he ascended to the papacy as Martin V (1417–1431).
With his passing, the palace was sacked during feuds, and the main property passed into the hands of the Della Rovere family. It returned to the Colonna family when Marcantonio I Colonna married Lucrezia Gara Franciotti Della Rovere, the niece of pope Julius II. The Colonna"s alliance to the Habsburg power, likely protected the palace from looting during the Sack of Rome (1527).
Starting with Filippo Colonna (1578–1639) many changes have refurbished and create a unitary complex around a central garden. Architects including Girolamo Rainaldi and Paolo Marucelli labored on specific projects. Only in the 17th and 18th centuries were the main facades completed. Much of this design was completed by Antonio del Grande (including the grand gallery), and Girolamo Fontana (decoration of gallery). In the 18th century, the long low facade designed by Nicola Michetti with later additions by Paolo Posi with taller corner blocks (facing Piazza Apostoli) was constructed recalls earlier structures resembling a fortification.
The main gallery (completed 1703) and the masterful Colonna art collection was acquired after 1650 by both the cardinal Girolamo I Colonna and his nephew the Connestabile Lorenzo Onofrio Colonna and includes works by Lorenzo Monaco, Domenico Ghirlandaio, Palma the Elder, Salviati, Bronzino, Tintoretto, Pietro da Cortona, Annibale Carracci (painting of The Beaneater), Guercino, Francesco Albani, Muziano and Guido Reni. Ceiling frescoes by Filippo Gherardi, Giovanni Coli, Sebastiano Ricci, and Giuseppe Bartolomeo Chiari celebrate the role of Marcantonio II Colonna in the battle of Lepanto (1571). The gallery is open to the public on Saturday mornings.
The older wing of the complex known as the Princess Isabelle"s apartments, but once housing Martin V"s library and palace, contains frescoes by Pinturicchio, Antonio Tempesta, Crescenzio Onofri, Giacinto Gimignani, and Carlo Cesi. It contains a collection of landscapes and genre scenes by painters like Gaspard Dughet, Caspar Van Wittel (Vanvitelli), and Jan Brueghel the Elder.
Along with the possessions of the Doria-Pamphilij and Pallavacini-Rospigliosi families, this is one of the largest private art collections in Rome.