Proceedings of the Xiith International Congress of the Int. Assoc. for the History of Religions, Held with the Support of UNESCO and Under the Ausp. of the Int. Council for Philos. and Humanistic Studies at Stockholm, Sweden, August 16-22, 1970
Geo Widengren was a Swedish historian of religions, professor of history of religions at Uppsala University, orientalist and Iranist. Widengren wrote a series of works on Iranian religions, Islam, Judaism, Gnosticism, etc. His most popular works include Die Religion Irans, published in 1965.