“Watts left formal Zen training in New York because the method of the teacher did not suit him. He was not ordained as a Zen monk, but he felt a need to find a vocational outlet for his philosophical inclinations. He entered Seabury-Western Theological Seminary, an Episcopal (Anglican) school in Evanston, Illinois, where he studied Christian scriptures, theology, and church history. He attempted to work out a blend of contemporary Christian worship, mystical Christianity, and Asian philosophy. Watts was awarded a master's degree in theology in response to his thesis, which he published as a popular edition under the title Behold the Spirit: A Study in the Necessity of Mystical Religion.

He later published Myth & Ritual in Christianity (1953), an eisegesis of traditional Roman Catholic doctrine and ritual in Buddhist terms. However, the pattern was set, in that Watts did not hide his dislike for religious outlooks that he decided were dour, guilt-ridden, or militantly proselytizing—no matter if they were found within Judaism, Christianity, Islam, Hinduism, or Buddhism.”

—- From the Wikipedia page.