According to chronicler Zurara, Gonçalo de Sintra was a young squire (escudeiro) or stirrup boy in the household of Portuguese prince Henry the Navigator, Duke of Viseu.
In late 1444 (or 1445), Henry dispatched Gonçalo de Sintra in command of a caravel on an exploratory expedition down the West African coast, with strict instructions to sail straight to the 'land of Guinea', and to not detract from that objective.
But Lançarote's raid had driven much of the local population to evacuate the islands and coasts, with the result that Sintra found the fishing settlements deserted.
According to Zurara, Gonçalo de Sintra directed his caravel to Nair island (ilha do Nar), at the southern end of Arguin bay.
Modern historians have tended to side with Zurara's identification of Nair, suggesting that Cintra Bay was probably named in error by contemporary Portuguese cartographers.