Christianity

Christianity was the intended religion of the Legend of Zelda series prior to the creation of the Golden Goddesses. Based on the real world religion, its existence is very vague, but it is implied throughout the early installments of the series.

The Legend of Zelda
The Book of Magic resembles a stereotypical depiction of the holy book of Christianity, the Bible, as it has a cross on its cover. The Magical Shield also has a cross painted on it.

Zelda II: The Adventure of Link
The Cross, a Christian symbol and relic is an obtainable item that is used to make invisible objects visible.

The Legend of Zelda: A Link to the Past
Although this game rang in the religion of the Golden Goddesses and the Triforce, official artwork was released regardless that depicted Link kneeling before a crucifix. Also in the Desert after using the Book of Mudora before entering the desert palace, Link performs the sings of the cross, a practice used by catholoism, the Largest Christian branch Relegion.