When my great grandfather travelled to the US in the late 1890s, his name was Harry Dubh (Irish for Black).
At Ellis Island, the people made him Anglosize his name. Call yourself Mr. Harry Black, they told him. he didn't want the surname. My name is Dubh, he told them. We'll put you down as Dobb, they told him. Och, no, he said. That's British. They made him settle for Daub. He never forgave Immigration.