Flag of the ancient Sultanate of Zanzibar.
Vectorized in vim by Mysid. Based on a PNG by User:Hierakares, who based it on a drawing and description in "Die Wappen und Flaggen der Herrscher und Staaten der Welt / J. Siebmachers großes Wappenbuch Band 1", reprinted by Bauer &amp; Raspe, Neustadt an der Aisch (Germany) 1978.
Mysid