Han-dynasty lodestone-spoon use is attested for divination, and Shen Kuo's 1088 description is the first clear account of a directional needle, but no source pins down exactly when navigational use began or documents a transmission route to Europe.
What would resolve this A dated Chinese or Islamic-world source describing shipboard compass navigation, or documentary evidence of a specific trade contact carrying the technology westward, would settle the timing and the transmission question respectively.
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