Delphi was a major sacred center of the ancient Greek world on the slopes of Mount Parnassus, where the Pythia delivered Apollo’s oracle on war, colonization, and state policy, and where the Omphalos marked the world’s center. Its sanctuary developed within a much older settled landscape, but most visible remains come from its flourishing in the sixth and fourth centuries BC, including the Temple of Apollo, treasuries, monuments, stoa, and theatre. Revered across the Greek world, Delphi expressed a shared Hellenic identity despite political rivalries. After pagan worship ended under Theodosius I, it remained inhabited for centuries before its ruins were excavated beginning in 1893.