According to rumors and legends, these Black Irish are the descendants of a few surviving ill-fated Spanish sailors who sailed with the Felícima Armada from Spain to invade England but were ultimately shipwrecked on the northern and western coasts of Ireland in the autumn of 1588. A very small number of the more than seven hundred Spanish men who made it alive to the Irish coast survived, and a few of those who did allegedly became intimate with enough Irish women so as to engender a new inter-racial strain of progeny whose "dark hair and eyes and soft brown Southern skin testifies to its remote Spanish ancestry."
This story has been retold by a number of Irish and Irish-Americans of this decade by way of explaining their own "dark hair and eyes" -- although from personal experience these facial characteristics have never been matched by a "brown Southern skin."