The original Pantheon was Agrippa’s brainchild.
Agrippa quickly established himself as a valuable civil aide, just as he had done in the military. He committed himself on restoring and enhancing Rome. Sadly, the Pantheon that is still standing today was not erected by Agrippa; rather, it is a replica that Trajan and Hadrian constructed after a fire destroyed the original.
The only surviving source of information from the time is Pliny the Elder's report of Diogenes of Athens' decorating of the edifice. The Caryatides, the female statues that adorned the temple's columns and ceiling and were all "viewed as master-pieces of excellence," were specifically mentioned by him. The capitals of the pillars resemble pieces of Syracuse bronze. The layout of the ancient building is still debated, but many historians and archaeologists believe it resembled the Pantheon, which still remains today, with the exception of the dome.
As a testament to the deep bond between Agrippa and Augustus, Agrippa initially wished to name the building the August Eum, and to place a statue of Augustus in the center of the main chamber. However, Augustus refused both of these honors, conscious of his shaky political position. Agrippa instead placed a statue of Julius Caesar in prominence in the inner chamber and statues of himself and Augustus in the antechamber, flanking the entrance.
