“Turbi e orbi” Latin means “whirlwind of world” in English (loses the meaning somewhat).
“Threshold: The esoteric significance of the threshold relates to its position in the passage from the external (profane) to the internal (sacred) state.…
“To stand at the threshold is to indicate one’s readiness to obey the rules by which the place is governed. …
“To stand at the threshold is also to place oneself under the protection of the master of the house, be he God, grandee or peasant.
“Crossing the threshold requires a degree of bodily purgation and purity of mind and soul, symbolized, for example, by the removal of one’s shoes before entering a mosque or a Japanese house.
“The threshold is the borderline of the holy and participation in the transcendence of the centre.”
-Jean Chevalier and Alain Gheerbrant, The Penguin Dictionary of Symbols, trans. John Buchanan-Brown, 1969
And Thanks to Susan Guthrie for finding this quote and art.