4 "Grecian" means "in a style used by the inhabitants of Greece," and so anyone could make, say, a Grecian urn. "Greek" means either an inhabitant of Greece, or from Greece, so a Greek urn must come from Greece. Keats, over a millennium and a half later, wrote an Ode to a Grecian Urn, in which the urn itself is the recipient/addressee.

Understanding the Context

Thou still unravish'd bride of quietness, Thou foster-child of silence and slow time, Sylvan historian, who canst thus express A flowery tale more sweetly than our rhyme: What leaf-fring'd legend haunts about thy shape ...