You may be interested in Ancient Pagan and Modern Christian Symbolism newly added this month over at Project Gutenberg.
“We search into emblems with an intention different from that with which we inquire into ordinary language. The last tells us of the relationship of nations upon Earth, the first of the probable connections of mankind with Heaven. The devout Christian believes that all who venerate the Cross may hope for a happy eternity, without ever dreaming that the sign of his faith is as ancient as Homeric Troy, and was used by the Phoenicians probably before the Jews had any existence as a people; whilst an equally pious Mahometan regards the Crescent as the passport to the realms of bliss, without a thought that the symbol was in use long before the Prophet of Allah was born, and amongst those nations which it was the Prophet’s mission to convert or to destroy. Letters and words mark the ordinary current of man’s thought, whilst religious symbols show the nature of his aspirations. But all have this in common, viz., that they may be misunderstood.”