AI overview
I don't have enough context to provide an accurate overview of "866" since only "year" is provided as the reference. Could you provide additional context about what specifically 866 refers to (a historical event, year, product, regulation, etc.)?
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Article
Fujiwara no Yoshifusa (804–872)
Year 866 (DCCCLXVI) was a common year starting on Tuesday of the Julian calendar.