“3. The following persons are Zanzibaris by birth:
(a) The child, whether born in our Dominions or not, of a Zanzibari father who was born in our Dominions or became our subject by naturalization.
(b) The child born in our Dominions of parents unknown or whose nationality is unknown.
(c) The child born in our Dominions of an alien father born in our Dominions.”
Download file: Zanzibar Nationality and Naturalization Decree 1911
Note that the Decree, which had been countersigned by the representative of the British government, had that countersignature revoked in 1913 (download here), meaning that the British did not recognise its application.