Question: What was the Pantheon used for, in the city that was central to imperial life in the early fifth century, for the empire that the term 'The West' comes from?

<P0-S0> Around 100 CE, it had a population of about 450,000, and declined to a mere 20,000 during the Early Middle Ages, reducing the sprawling city to groups of inhabited buildings interspersed among large areas of ruins and vegetation. <P0-S1> For almost a thousand years, Rome was the most politically important, richest and largest city in Europe. <SEP> <P1-S0> The Eastern Mediterranean was home to the highly urbanized cultures that had Greek as their common language (owing to the older empire of Alexander the Great and of the Hellenistic successors), whereas the West was much more rural in its character and more readily adopted Latin as its common language. <P1-S1> After the fall of the Western Roman Empire, Western and Central Europe were substantially cut off from the East where Byzantine Greek culture and Eastern Christianity became founding influences in the Arab / Muslim world and among the Eastern and Southern Slavic peoples. <P1-S2> Roman Catholic Western and Central Europe, as such, maintained a distinct identity particularly as it began to redevelop during the Renaissance. <P1-S3> Even following the Protestant Reformation, Protestant Europe continued to see itself as more tied to Roman Catholic Europe than other parts of the perceived civilized world. <P1-S4> The geopolitical divisions in Europe that created a concept of East and West originated in the Roman Empire. <SEP> <P2-S0> philadelphia's central city was created in the 17th century following the plan by william penn's surveyor thomas holme. <P2-S1> center city is structured with long straight streets running east-west and north-south forming a grid pattern. <P2-S2> the original city plan was designed to allow for easy travel and to keep residences separated by open space that would help prevent the spread of fire. <P2-S3> the delaware river and schuylkill rivers served as early boundaries between which the city's early street plan was kept within. <P2-S4> in addition, penn planned the creation of five public parks in the city which were renamed in 1824 (in parenthesis): centre square, north east publick square (franklin square), northwest square (logan square), southwest square (rittenhouse square), and southeast square (washington square). <P2-S5> center city has grown into the second-most populated downtown area in the united states, after midtown manhattan in new york city, with an estimated 183,240 residents in 2015. <SEP> <P3-S0> the term "great plains", for the region west of about the 96th or 98th meridian and east of the rocky mountains, was not generally used before the early 20th century. <P3-S1> nevin fenneman's 1916 study, physiographic subdivision of the united states, brought the term great plains into more widespread usage. <P3-S2> before that the region was almost invariably called the high plains, in contrast to the lower prairie plains of the midwestern states. <P3-S3> today the term "high plains" is used for a subregion of the great plains. <SEP> <P4-S0> The present building was completed by the emperor Hadrian and probably dedicated about 126 AD. <P4-S1> The Pantheon (/ ˈpænθiən / or US: / ˈpænθiɒn /; Latin: Pantheum, from Greek Πάνθειον Pantheion, ``(temple) of all the gods '') is a former Roman temple, now a church, in Rome, Italy, on the site of an earlier temple commissioned by Marcus Agrippa during the reign of Augustus (27 BC -- 14 AD). <P4-S2> He retained Agrippa's original inscription, which has caused confusion over its date of construction as the original Pantheon burned down, so it is not certain when the present one was built.