THEORIA IN GREEK RELIGION
What was the Greek for pilgrim? If there is no simple answer, the explanation is the great diversity of ancient pilgrimages and pilgrimage-related phenomena. People went to sanctuaries for all sorts of reasons: consulting oracles, attending festivals, making sacrifices, watching the Panhellenic games, or seeking a cure for illness; there were variations in the participants (individuals or state-delegations, small groups or large), and variations in the length of distance traversed to get to the sanctuary; finally, changes occurred in the shape of pilgrimage over time: pilgrimage is not the same in the Hellenistic period as it is in the classical period, and pilgrimage in the Roman world is different again.
If we limit our scope to state-pilgrimage and to the classical period, we find a special vocabulary for pilgrimage in the word θεωρός and its derivatives θεωρέω, θεωρία, and θεωρίς2. θεωρία is the normal term for state-pilgrimage, as we see in the famous introduction to Plato's Phaedo (58b) describing the Athenian pilgrimage to Delos. The corresponding term for a pilgrim is θεωρός, found first in Theognis (Eleg 776), and frequently in the fifth century. The verb θεωρέω can mean ‘go on a pilgrimage to’, as in Thucydides' account of Ionian pilgrimage to the Delian festival (3.101). θεωρίς is the normal Attic term for a sacred ship used to convey sacred delegates to and from a sanctuary. One area where this family of words is never used is that of pilgrimage to healing sanctuaries; if we find any word used there, it is ἱκέτης, in later texts sometimes the neutral σνμϕοιτητής.