Van Dyke Addams is a relative of The Addams Family.
He was Gomez Addams' great-great-great-great-grandfather (though later he is given another 'great') who helped purchase Manhattan Island from the Indians. Gomez and Morticia found a statue of him in a display in New York's Museum of Natural History. He was bequeathed New York's Central Park as an inheritance by Chief Powhattan.
The Addams Family (animated 1973) episode:
The Gold Key comic book: