CR ritual structures are based on the ancient Celtic cosmology of the `` Three Realms '' - Land , Sea and PERSON@1 , PERSON@2 -LRB- NUMBER@1 -RRB- `` Irish Perceptions of the Cosmos '' Celtica vol .

CR ritual structures are based on the ancient Celtic idea of the `` Three Realms '' - Land , Sea and PERSON@1 , PERSON@2 -LRB- NUMBER@1 -RRB- `` Irish Perceptions of the Cosmos '' Celtica vol .
