Priests and Priestesses had an important role in Ancient Greece. Their duties were different but mostly they performed sacred rituals.
In ancient Greece, both men and women could become priests and priestesses. In most cases, it was a custom that priests were the same sex as the god they served. Most women who became priestesses were either virgins or beyond child bearing age.
In order to become free of harm, ancient Greek priests and priestesses wore a sacred headband. Their main duties were to carry out religious ceremonies and prayers.
Though ancient Greeks worshipped a number of gods, they the most important gods, were the Olympian gods led by Zeus. These were Athena, Apollo, Poseidon, Hermes,Hera, Aphrodite, Demeter, Ares, Artemis, Hades, Hephaistos, and Dionysos. These gods were believed to reside on Mt. Olympos. Gods were worshipped at sacred sites and temples in all major Greek communities in ceremonies carried out by priests and their attendants.
Different priests served different gods, but they were not necessarily religious experts.
A Greek citizen who wished to get an answer to a religious question could visit exegetes, a state official, who was knowledgeable in religious matters.
In addition to the formal and public religious ceremonies there were also many rites which were open to and known only by the initiated who performed them, the most famous example being the Mysteries of Eleusis. In these closed groups, members believed that certain activities gave spiritual benefits, amongst them a better after-life.
There were also places that could also acquire a divine connection. These were known as the great oracles. One of the most famous oracles is that of Apollo at Delphi and Zeus at Dodona.
Oracles were sacred sites where people considered particularly good to receive signs from the gods. Such places became hugely important centers with their priest oracles consulted by both individuals and city-states.