A male heir —usually describing the first-born son (primogeniture) or oldest surviving son of a family—has traditionally been the recipient of the residue of the estate, titles, wealth and responsibilities of his father in a patrilineal system. This system may vary by region but has ancient, perhaps prehistoric, origins, and appears in the Code of Hammurabi: "Since daughters marry strangers and thereby cut themselves off from their family, only sons inherit the paternal estate. It is they who perpetuate the family name, and preserve the ancestral property."