Remember, too, Cape Verde *was* a part of Portugal at that time. It didn't gain its independence from Portugal until 1975 when it became the Republic of Cape Verde. So naturally many of the people who lived in or came from CVI would identify as Portuguese and not necessarily Cape Verdean (although some seemed to .. maybe those with fewer ties to the continent?). Their passports would identify them as Portuguese citizens, just as someone from the Azores would. Same as someone born & raised in Hawaii would have a US passport and not a separate Hawaiian passport, or someone born & raised in Alaska has a US passport and not a Canadian passport. You get the idea. ;) Prior to 1975 someone from CVI's nationality was Portuguese regardless of the person's ancestry (Portuguese, British, Italian, African, etc.). So it's not really that it wasn't "acceptable" to say you were Cape Verdean prior to 1975, it was that Cape Verde was not an independent nation prior to that time. It's pretty cool, but it can also be very complicated when researching.