The Pantheon (Latin: Pantheon, from Greek Πάνθεον meaning "every god"), an ancient building in Rome, Italy. Built in 118–128 AD. on the site of an earlier building 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.
It is one of the best-preserved of all Ancient Roman buildings. It has been in continuous use throughout its history, and since the 7th century, the Pantheon has been used as a church dedicated to "St. Mary and the Martyrs" (Latin: Santa Maria ad Martyres) but informally known as "Santa Maria Rotonda". The present high altars and the apses were commissioned by Pope Clement XI (1700–1721) and designed by Alessandro Specchi. Enshrined on the apse above the high altar is a 7th-century Byzantine icon of the Virgin and Child, given by Phocas to Pope Boniface IV on the occasion of the dedication of the Pantheon for Christian worship on 13 May 609. The choir was added in 1840, and was designed by Luigi Poletti.
more on https://en.wikipedia.org/wiki/Pantheon,_Rome