Over time, the Aetolians succeeded in control over Delphi after the Macedonians. In 279 BC, Brennus and his Gauls invaded, attempting to sack the temple. They advanced along the same route as Xerxes' Persians and were repelled and defeated in the same miraculous manner.

In 189, the Aetolians were defeated by the Romans, who gained control of Delphi. The oracle began to lose both power and respect, and was even plundered by Sulla in 86 BC. Until its eventual demise, Delphi's fortunes now rose and fell with the favor of each Roman Emperor, who sometimes rebuilt and sometimes raided Delphi. The last emperor to consult the oracle was the pagan emperor Julian (361-363 AD). In 395 AD, the oracle at Delphi was finally abolished by the Christian emperor Theodosius.